@GasPanic
For example, if you had a fried chicken shop, you could take the cash and launder it, but an investigator taking a look at the accounts might ask the question where are the incoming purchases (chicken?). I don't know whether a refurb would be hidden in cost of sales and therefore appear as an expense instead of the chicken, allowing the books to stand up better to scrutiny.
What happens in reality is that in such a scenario, they buy lots and lots of chicken, "sell" some of it legitimately, but throw away most of it. By pretending to have sold it all, they can put a lot of dirty cash through the till as chicken sales. The sales to purchases margins/percentages look OK, as the till shows the right amount of takings for the right amount of chicken bought, so the accounts/tax returns look right. A big "giveaway" as to what they're doing is to look at the costs of their waste disposal - higher than normal numbers of collections is a good sign (though lots will just fly tip it!). Another giveaway is where they're not too bright and don't buy a matching amount of polystyrene trays to match the amount of chicken they claim to sell (HMRC routinely check the amount of Poly trays to check for too many (pocketing cash sales) or too few (money laundering through not selling as much as the takings show).
Any high profit product (i.e. food takeaway) or service (hairdresser, nail bar, tattoo bar, etc) can work that way. The bigger the gap between buying what they sell and the sale price the better.
Paying for refurbs is actually the icing on the cake, as the newly "cleaned" money can be paid on to friends/family "pretending" to do the refurb, to reduce the profits of the money laundering chicken takeaway so they pay less tax. The "cleaned" money is funnelled to others for usually overpriced or unnecessary construction work. In reality, the owners of the construction firm are probably "uncles" of the chicken shop owner, so monies are just being redistributed around the family which is pretty normal in some ethnic minority extended families as they tend to look out for each other rather than borrowing loans etc and there's usually lots of "loans" pinging around between generations and linked/extended families.