My uncle told me about this. He said he used to use it on his old Vette in the 80's...so i'm assuming this idea has been around even longer than that? It def works.
And a crease is like if you karate chopped a beer can and tried to pop the can back to its normal shape (won't work)....vs if you pushed in on the side with your thumb when drinking it, then realized you dented and and popped it back out.
