This is a good topic to discuss "hidden" or unreported cash income. A car wash is one of the businesses that are sometimes attractive to potential buyers because they think a lot of cash changes hands and a lot can end up in the owner's pocket without paying state and federal taxes.
A seller who is going to tell you all about the taxes he hasn't paid on cash is telling you that he routinely steals, cheats, and lies -- but, he wants you the buyer to believe him when he tells you about his business. How trustworthy is that?
Material non-reporting of income distorts the entire system.--Those of us who are honest about our earnings are consequently paying a disproportionately higher amount of government expenses. How fair is that?
And, taking over a business with the intention of becoming an immediate tax felon can cost you bundles in legal fees, fines, and lost income, no to mention the prospect of looking through bars for several years.
How smart is that?
Car washes, laundromats, vending routes ... these can all be good businesses. But, they must be sound businesses based on actual reported income, not based on being a criminal enterprise.