Gave tenants a warning once already. 2nd time?

[Jonathan Perez]

So I had asked my tenant to pick up the cigarette butts ONCE already, maybe about a month ago. When I was mowing the lawn last night I notice 2 or 3 butts and two bottle caps on the drive way... as I went to the back part I noticed that there garbage bin was full to the top. (Not sure about the garbage being an issue but I feel like they should be on top of that and should bring it to the front when weekly for pick up) What should I do? Give them another warning orrrr? I was thinking I should've took pictures and sent them to my PM and had him send them a letter of warning that next time there will be a fee. What do you guys think? It may be awkward when I see them after doing that but I don't care. *shrugs* I just don't wNt to be in the wrong. I want to show them that I'm cool, as long as they do they're part that's all. Thanks.