[Ethereum] How to Retrieve Remaining Tokens from ICO Contract

contract-developmenticosolidity

So I created an ICO contract based on a token with a set initial supply and no mint function. I publish this contract and then send the associated tokens to the contract. I can send ether and receive it in the desired account and the new tokens are sent to the correct account.

However, if not all of the tokens that were sent to the contract are purchased during the ICO, they just seem to disappear. Is there a simple way to retrieve the remaining coins? I have tried self destruct and suicide but I think those apply to the ether that would be stored in the contract address.

Thanks for any help!

Brian

Best Answer

If your contract(s) are already deployed, you're out of luck.

On the other hand if you are still developing either the token or the crowdsale, there are a number of ways you can move the tokens around.

Firstly, the token balance on your crowd sale contract is just a value allocated within the token contract, so you can just have a function on your token contract allow you to directly reassign the balance from the crowd sale contract.

uint256 unsold = balances[saleaddress];
balances[saleaddress] = 0;
balances[someLocation] += unsold;

A better option perhaps, is to have the crowd sale contract handle it. In this case you can do something like

function withdrawUnsoldTokens()
{
    require(msg.sender == ownerAddress);
    ERC20 mytoken = new ERC20(tokenAddress);
    uint256 unsold = mytoken.balanceOf(this);
    mytoken.transfer(ownerAddress, unsold);
}

No

In your function that calls selfdestruct(owner), you would also need need to call the (ERC20) token's contract transfer function. The code would look like:

SomeToken tok = SomeToken(tokenAddress);
uint tokenBalance = tok.balanceOf(address(this));
tok.transfer(owner, tokenBalance);

Make sure that owner is an externally owned account (EOA) or a contract that can access the tokens.

Reminder to test thoroughly, that the tokens are transferred and that the owner can transfer the ETH and tokens it receives.

The other case is what @Ian mentions and if your contract issued tokens to people, and you selfdestruct the contract, people's tokens disappear: your contract was the ledger that recorded token balances and it disappeared.

ERC20 Token Management – Total Supply, Minting, and Burning Strategies

For question 1 I think you're point about the scale being important is correct, buying something with 10 tokens instead of .0000001 or 1000000 tokens. You should come up with a best estimate of the range you expect the market cap to be and have the supply be within an order of magnitude of that so the range of normal amounts is what most people are used to dealing with.

As for minting/burning, this is dependent specifically on the project. MKR for example is minted only in the case of under-collateralization in an effort to pay off debt via inflation, and it's burned whenever someone uses it to pay off debt. Many tokens just don't have any minting or burning. It completely depends on how the economics are supposed to work.

Best Answer

Related Solutions

[Ethereum] Will contract selfdestruct also return tokens

No

ERC20 Token Management – Total Supply, Minting, and Burning Strategies

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