The best guidance is the link on this thread - the ADN one.
We have given our clients an instruction sheet, that so far they seem happy with. So sheets and towels placed in a big washing bag, things like books and CD that they’ve used in final 3 days of their stay placed in a basket, requesting hand-washing before putting away crockery and cutlery and hot not eco cycle on dishwasher, open windows etc before they leave. Beyond that it’s a choice, and people who have wanted to cancel have been given full refunds instantly.