Earlier this year, I had a grade 9 student (a daughter of a friend of mine) come to my house from 9-11am to help with the kids snacks, walks, and lunch prep.
She was able to use it towards her high school volunteer hours (Mandatory in Ontario).
I simply filled out her sheet and how many hours she helped out for. Its a win win for us, so why not?
You could always advertise on Kijiji directing your ad towards highschool students looking to complete community service hours.