You're going to get a nasty dose of truth about the fungibility of BTC if you end up with tainted BTC and try to cash them out on an exchange.

There are some crypto that are practically fungible (although technically not). Look into privacy coins.

The bitcoin protocol seems to go out of its way to ensure that's not true. Bitcoin balances can never be consolidated - you don't pay bitcoin out of a wallet with fungible coins in it; you pay bitcoin out of a globally-unique transaction pointed at the wallet.