It's harder and harder to find ways to wash it. The feds are all over it now, it's not as anonymous and mysterious as it was back in the day, they can trace the blockchain for sure, but to what extent we don't know. They withheld so much shit on a lot their court cases, because they didnt want to prove how they track even the biggest time people. I haven't followed it in ages now, but I know for a time, to wash the cut was over 30%, so they likely didn't want to take any chances letting btc dip in price while holding cause the margins get thin