I have been making balls with this mould for several years now with outstanding results. After every session I let it cool and oil it with WD40 before putting it up. Before using it again, I clean the mould with denatured alchohol before heating it up. The last time I used it there was a consistant wrinkle on the side of the ball. I realize I did something wrong here but do not know what or exactly how to fix it. I tried putting the alchohol on some 0000 steel wool, put the wool on a Q-tip and cleaning the cavity, but to no avail. I'm not sure how much this wrinkle will affect accuracy, especially at longer ranges. I use the balls for a 200 yard steel silhouette match. HELP! ::