I have been using a Marsal proofing box for that last couple weeks and have been having trouble with the dough getting a skin on the sides. I was using plastic wrap to cover the dough before and that was working fine. If I take the plastic wrap off it will form a skin on the dough in about 10 minutes. Can someone tell me why that is happening. I just made a cover for my box, I just checked the dough and there is a skin only around the sides but the top is fine. I haven't lifted the lid since I put the dough for a bulk rise in the box for 8hrs. I am about to ball the dough, can someone tell me how I can get the dough to stop forming a skin on it. Also before when I was using the plastic wrap the bottom of the dough would keep moist but there would be a little ring on the bottom edge of the dough that would form a skin also. It is kinda hard to explain what I am talking about, I will take a picture if it happens again and post it so you can see.