Deck needs stained--how best to ask or tell tenant to prepare?

[Jody Powell]

Our rental house needs the deck stained and I realized that my lease does not spell out how to handle this situation: Our tenants have been in the house for a year and a half now and a lot of stuff has accumulated on the large deck. How do you deal with asking (or telling?) the tenant they will need to clear the deck for this? Maybe I am overthinking this...