Shellac is practically impenetrable, but I must get it off. The lilac color has been on for too long & I’m over it. The only way to get the shellac off is soak my toes in acetone for at least 15 minutes. Don’t worry, I used time lapse so I could get to the good stuff. Scraping all of that shellac off with an orange stick then rubbing my feet down with coconut oil, since the acetone dried them out so much.