How long to I keep aloe vera on scars?

k, so i have a lot of scars (do not comment on it, just plz answer the question), so i got some aloe vera gel. how long to i keep it on my legs? and do i just spread it on my legs and let it set? and how do i wash it off? thanks in advanced|||I believe you use it as you use lotion..w/o washing it off.