RE: Mold and moisture ... Cold at nite. Sun hits the pit in the day. The dark cover absorbs heat = condensation. Add rain or melting snow that migrates thru the stitching = water.. Propping the lid open 1/8" to 1/4" with the cover on will help..Adding some sort of spacer, ie, 1/4" thick pvc (wont hold moisture) between the pit and cover, on top, to provide a small air space helps even more..If the pit hasn't been used after a rain or snow fall, remove the cover and hang to dry. Fully open the pit and let the air and sun in. Helps with rust too.