Bitcoin is an attractive option for money launders primarily because laundering money using cryptocurrencies is easier than other methods. In movies, criminals often transport illicit money across borders using duffel bags or suitcases to evade authorities; however you can trade with dirty bitcoin beacuse more sallers of dirty bitcoin take only 60 percent of full order price
more about dirty bitcoin and how to raise money on that in my tg @ malfa1teur
What is your definition for dirty bitcoin?
One Bitcoin transaction is made up of inputs and outputs and are you sure that bitcoins you own in your wallets are not dirty?
If initially your bitcoins are clean, but I doubt it, and you send it to centralized exchanges, trade there or just deposit and leave it there, then withdrawal, you will receive bitcoins from other UTXOs which are not sure to be clean or dirty.
Money laundering is everywhere and can be done by any means from fiat currency through digital bank transfer, cash, other means like gold, diamond and don't assume it only can be done with Bitcoin transactions.
Forget your belief that you can know and get clean or dirty bitcoins. It is non sense and you can not have any practice to make sure your coins are clean or dirty.