Ply-grip: Our worst enemy and our best friend. The sharp metal teeth you find on large sections such as the back and sides are called Ply-grip. You will want to be careful with these pieces because they are very sharp. The best way to open them is using a butter knife to pry it open (seen in the next picture). Because I wanted to keep costs as low as possible, I wanted to reuse the ply-grip, so I made sure not to bend everything out of place too badly. You can grip the fabric with your pliers and just pull it out of the ply-grip.