Tutorial: How to Revoke Old Bridge Approvals After Moving ETH to PulseChain

December 1, 2025 — When you bridge ETH to PulseChain, you grant the bridge contract "approval" to spend your tokens—often unlimited. Once your bridge is complete, this approval remains active, creating ongoing security risk. If the bridge is ever exploited, attackers could drain wallets with active approvals—even if you're not actively using the bridge. This tutorial shows you exactly how to revoke these approvals in 5 minutes, protecting your funds. Essential security practice for every bridge user.

💡 Just completed your first bridge? Great! Now learn this essential security step. (New to bridging? Start with our ETH to PulseChain bridge guide first.)

Why Revoking Approvals Matters

The Hidden Risk

When you bridge tokens, here's what happens behind the scenes:

1. You click "Approve" before bridging
2. This grants bridge contract permission to access your tokens
3. Often, approval is UNLIMITED (not just for your current bridge)
4. This approval remains active forever (unless you revoke it)

Real-World Example: Why This Is Dangerous

August 2024: Multichain bridge exploited. Attackers gained control of bridge contract. Result: Anyone who had ever approved Multichain could have their tokens drained—even if they hadn't used the bridge in months. Total losses: $126M.

If users had revoked approvals after bridging, their funds would have been safe.

Understanding Token Approvals

What Is a Token Approval?

Token approval = permission slip

You're telling a smart contract: "You can access up to X amount of my [TOKEN]"

Types of Approvals

• Limited approval: "You can access 0.5 ETH" (safer)
• Unlimited approval: "You can access all my ETH, forever" (convenient but risky)

Most bridges use unlimited approvals by default (including PulseChain Bridge, for UX reasons)

Why Do Bridges Need Approvals?

Bridges need permission to "pull" tokens from your wallet. Without approval:

• Bridge can't access your tokens
• Bridge transaction would fail
• You couldn't bridge at all

The problem: Approval doesn't expire after one use. It stays active until you manually revoke it.

Step-by-Step: Revoking Bridge Approvals

Method 1: Revoke.cash (Recommended - Easiest)

Step 1: Navigate to Revoke.cash

1. Open your browser (Chrome, Firefox, or Brave)
2. Go to https://revoke.cash
3. ⚠️ Verify URL is correct (bookmark for future use)

Step 2: Connect Your Wallet

1. Click "Connect Wallet" (top-right)
2. Select "MetaMask" (or your wallet)
3. MetaMask popup appears
4. Click "Connect"
5. Select account with bridge approvals
6. Click "Connect" again

Step 3: View Your Approvals

Revoke.cash automatically scans your wallet and shows:

• All active approvals
• Which contracts have access
• How much they can access (unlimited vs. limited)
• When approval was granted

Look for: Approvals to "PulseChain Bridge" or other bridge contracts

Step 4: Identify Bridge Approvals

Each approval shows:

• Token: ETH, USDC, DAI, etc.
• Spender: Contract name (e.g., "PulseChain Bridge")
• Allowance: "Unlimited" or specific amount
• Risk level: Color-coded (red = high risk)

Step 5: Revoke Unnecessary Approvals

1. Find approval you want to revoke
2. Click "Revoke" button (right side)
3. MetaMask popup appears showing gas fee
4. Gas cost: $3-8 per approval
5. Click "Confirm"
6. Wait for transaction confirmation (1-2 minutes)
7. Approval now shows "Revoked" ✅

Step 6: Verify Revocation

1. Refresh Revoke.cash page
2. Revoked approval should disappear from list
3. Or show $0.00 allowance

Method 2: Etherscan (Alternative Method)

Step 1: Navigate to Etherscan

1. Go to https://etherscan.io
2. In search bar, enter your wallet address
3. Press Enter

Step 2: Find Token Approvals

1. On your address page, click "More" dropdown
2. Select "Token Approvals"
3. List of all approvals appears

Step 3: Connect Wallet to Revoke

1. Click "Connect to Web3" (top-right)
2. Select MetaMask
3. Approve connection

Step 4: Revoke Approvals

1. Find bridge approval in list
2. Click "Revoke" link
3. Confirm transaction in MetaMask ($3-8 gas)
4. Wait for confirmation

Which Approvals Should You Revoke?

Priority 1: ALWAYS Revoke (High Risk)

• ✅ Bridges you've stopped using (e.g., old ETH → PulseChain bridge after you're done)
• ✅ Unlimited approvals (shows "∞" or "Unlimited")
• ✅ Unverified contracts (shows warning on Revoke.cash)
• ✅ Protocols you don't recognize

Priority 2: Consider Revoking (Medium Risk)

• ⚠️ Bridges you use occasionally (revoke, re-approve when needed)
• ⚠️ Old DeFi protocols (low activity = higher hack risk)
• ⚠️ Large allowances (>$1,000 worth)

Safe to Keep (Lower Risk)

• 🟢 Bridges you use weekly (but monitor regularly)
• 🟢 Trusted DeFi protocols (Uniswap, Aave, etc.—but still limit exposure)
• 🟢 Limited approvals (specific amounts, not unlimited)

Post-Bridge Approval Checklist

Immediately After Bridging

• ✅ Confirm bridged tokens arrived on PulseChain
• ✅ Wait 24 hours (ensure no issues with bridge)

24-48 Hours After Bridge

• ✅ Visit Revoke.cash
• ✅ Connect wallet
• ✅ Revoke bridge approvals (if you're done bridging)
• ✅ Cost: $3-8 in gas per approval

If You Plan to Bridge Again

Option A: Keep approval active (convenient but risky)

Option B: Revoke now, re-approve later ($3-8 × 2 = total $6-16 in gas)

Recommendation: If you won't bridge again for >1 month, revoke. Re-approving costs $3-8 but protects against exploits.

Common Questions & Scenarios

Q: What happens if I revoke and then want to bridge again?

A: You'll need to approve again (one-time $3-8 gas fee). Bridge will prompt you automatically. It's the same process as your first bridge.

Q: Will revoking affect my already-bridged tokens on PulseChain?

A: No. Revoking only removes future access. Your tokens on PulseChain are unaffected.

Q: How much does revoking cost?

A: $3-8 per approval (varies with gas prices)

• Low gas (<20 gwei): $3-4
• Medium gas (30-40 gwei): $5-6
• High gas (>50 gwei): $7-10

Q: Can I revoke multiple approvals at once?

A: No, each revocation is a separate transaction (separate gas fee). However, you can batch them in quick succession.

Q: What if bridge is exploited before I revoke?

A: If you have active unlimited approval:

• Attacker could drain your tokens
• You'd lose up to the approved amount
• No recourse (it's technically "authorized")

This is why revoking is critical.

Advanced: Approval Management Strategy

Strategy 1: Revoke Everything After Use

Best for: Security-conscious users

Process:

1. Use protocol/bridge
2. Revoke approval immediately after
3. Re-approve next time you use it

Cost: $3-8 per revoke + $3-8 per re-approve = $6-16 total per usage cycle

Security: Maximum

Strategy 2: Monthly Approval Audit

Best for: Active DeFi users

Process:

1. Set monthly calendar reminder
2. Visit Revoke.cash on 1st of each month
3. Review all approvals
4. Revoke anything unused in last 30 days

Cost: $10-30/month (depending on # of approvals)

Security: High

Strategy 3: Limited Approvals Only

Best for: Power users

Process:

1. Never approve unlimited amounts
2. Manually set approval to exact amount needed
3. Approval expires after that amount is used

How to do this:

• When bridge asks for approval, click "Edit"
• Change "Unlimited" to specific amount (e.g., 0.5 ETH)
• Approve
• After bridging 0.5 ETH, approval is depleted (no revoke needed)

Cost: Same as unlimited approval, but auto-expires

Security: Very high

Security Best Practices

Prevention (Before Bridging)

• ✅ Only approve exact amount you're bridging (not unlimited)
• ✅ Use trusted bridges only (verified contracts)
• ✅ Set calendar reminder to revoke after bridge

Maintenance (Ongoing)

• ✅ Monthly approval audit via Revoke.cash
• ✅ Revoke approvals for protocols you no longer use
• ✅ Keep gas funds ready for emergency revocations

Emergency (If Bridge Is Exploited)

• ✅ Immediately revoke ALL approvals to that contract
• ✅ Move remaining funds to new wallet
• ✅ Monitor wallet for 24 hours for suspicious activity

Tools for Approval Management

Revoke.cash

• URL: https://revoke.cash
• Cost: Free (just gas fees)
• Features: One-click revoke, risk indicators, multi-chain support
• Best for: Everyone (easiest to use)

Etherscan Token Approvals

• URL: https://etherscan.io
• Cost: Free
• Features: View approvals, revoke directly on-chain
• Best for: Users who prefer official block explorer

Unrekt by Consensys

• URL: https://app.unrekt.net
• Cost: Free
• Features: Security alerts, approval monitoring
• Best for: Advanced users wanting real-time monitoring

Real Cost-Benefit Analysis

Scenario: You bridged 1 ETH, granted unlimited approval

Action	Cost	Risk Reduction
Do Nothing	$0	0% (full exposure)
Revoke Approval	$5	100% (protected)

If bridge is exploited and you didn't revoke:

• Potential loss: All remaining ETH in wallet (could be $1,000-$10,000+)
• Cost to prevent: $5
• ROI of revoking: 20,000%+ (if exploit occurs)

Conclusion: $5 for Peace of Mind

Revoking bridge approvals takes 5 minutes and costs $3-8. It's the single most important post-bridge security action—yet 90% of users skip it.

Your action plan:

1. Complete your bridge to PulseChain
2. Wait 24 hours (confirm tokens arrived)
3. Visit Revoke.cash
4. Revoke bridge approvals (especially if done bridging)
5. Repeat monthly for all protocols

Remember: Every bridge exploit in crypto history could have been mitigated by users who revoked approvals after use. Don't be the person who loses funds because you saved $5. 🔒

Need to bridge first? Follow our complete ETH to PulseChain bridge guide, then come back here to revoke approvals for maximum security.