i was a little leary about leaving it on for 3 weeks because of what most were saying about it becoming gooey if left on for more than a few days. i guess i'm lucky. no mess left at all after 3 wks. could have gone longer. didn't have to do a mirror slide. didn't even have to clean it. not even any residue on base. any cleaning of the base was just from the normal shampooing/rinsing of unit. plus i was able to contour the contours as i was applying around the perimeter and didn't even need to do any cutting of the strips. i think it would have been easier using 2 c contours and 2 cc contours. hoping cc will become available for sale on Debbie's web site.