How to Revoke Token Allowances on Ethereum, Arbitrum, & BSC

#Cut the Cord: Revoking Unlimited Token Allowances on EVM Chains

When participating in airdrop farming across EVM-compatible networks (like Ethereum, Arbitrum, BNB Chain, Polygon, etc.), you constantly interact with new smart contracts. Every time you swap, stake, or provide liquidity, your wallet is prompted to grant a Token Allowance (also known as a token approval).

Understanding and managing these allowances is the single most important security practice on EVM.

1. What is a Token Allowance?

A Token Allowance is the permission you grant a smart contract to move a specific amount of one of your tokens on your behalf.

• The Approval: You sign a transaction authorizing a dApp’s contract (the Spender) to transfer your tokens (the Owner) up to a specified amount (the Allowance).
• The Risk: Most dApps default to asking for an “Unlimited” allowance. This is convenient because you only pay the gas fee once, but it means that contract can technically drain your entire balance of that token forever.

The Danger of Unlimited Allowance

If a protocol you granted unlimited access to is later hacked, exploited, or turned malicious, the attacker can use the existing permission to call the contract and drain your wallet of the approved tokens without any further action or signature from you.

Disconnecting your MetaMask or Trust Wallet DOES NOT remove this permission! The permission is written to the blockchain.

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2. The Solution: Multi-Chain Revocation with Revoke.cash

To maintain a secure “Wallet Hygiene,” you must periodically check your allowances and revoke any that are unnecessary. The most widely recognized and easiest tool for this across all major EVM chains is Revoke.cash.

Step-by-Step Revocation Guide:

Follow these steps using your Burner Wallet (or any wallet you use for farming) to manage your allowances.

1. Access the Revoke Tool:

• Navigate to the official Revoke.cash website. Always verify the URL is correct to prevent phishing.

2. Connect Wallet and Select Network:

• Click ‘Connect Wallet’ (e.g., MetaMask, WalletConnect).
• IMPORTANT: Use the network selection menu (usually in the top right) to choose the blockchain you want to audit (e.g., Ethereum, Arbitrum, BNB Chain, Polygon). You must check each chain separately!

3. Review Active Allowances:

• The tool will scan the selected network and display a list of all your active token allowances.
• The list shows:
  • The Token (e.g., ETH, USDC, DAI).
  • The Spender (the contract that has permission).
  • The Allowance Amount (often displayed as “Unlimited” or a very large number).

4. Identify and Prioritize Revocations:

• Priority 1: Revoke unlimited allowances for high-value assets (USDC, USDT, ETH) on platforms you no longer use.
• Priority 2: Revoke any approvals for tokens from projects you suspect might be scams or have minimal TVL (Total Value Locked).

5. Execute the Revocation Transaction:

• Click the ‘Revoke’ button next to the specific allowance you want to cut off.
• Your wallet (e.g., MetaMask) will prompt you to sign a transaction. This transaction calls the original token contract and sets the allowance to zero (0).
• Gas Fee: Note that revoking an allowance is a transaction written to the blockchain, and therefore costs a small amount of the native currency (e.g., ETH on Ethereum, BNB on BSC, or ARB on Arbitrum) to pay the gas fee.

6. Confirmation:

• Once the transaction confirms on the blockchain, the contract’s permission is permanently removed.

Pro-Tip: Setting Custom Allowances

To prevent the need for constant revocation, many wallets (like MetaMask) allow you to edit the spending limit when prompted for an approval:

• When the approval pop-up appears, look for the ‘Edit Permission’ or ‘Custom Spend Limit’ option.
• Instead of leaving it as “Unlimited,” enter a specific amount slightly higher than your planned transaction (e.g., if you plan to swap $100 USDC, set the allowance to $110 USDC).

This limits the potential damage of an exploit, but you will have to re-approve the contract when you exceed that custom limit.

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