oil doesnt flow into the catch can unless your giving it a massive hammering and have too much oil in there to begin with
out of the 4 services i have done since i have had the car (4 months) i have never had more than a dribble in the catch can
na trust me, its good shit 'n shit!
i used it on the weekend, after the polish and wax i gave it 2 weeks ago,
get the next gen. tech detailer, and the meguires micro fibre clothes,
no scratches what-so-ever!