The first part of your post reminded me of the TV series Breaking Bad where they use the car wash as a cash-based business for laundering their cash.
The more modern Bitcoin mixer is probably a better way as I am sure that a real business will eventually be found out. Also, with more secure cryptocurrencies like Monero it is very difficult to track the source of a transaction.
In fact I was inspired by a Quora participation where the author cited a car wash. It would be that he did it based on Breaking Bad?