I have tried permatex and others. It's completely clean ever time. I'm like a expert at getting that thing off by now lol. Seriously I can pull it off in 10 minutes flat lol. I have replaced that bottom seal 2 times. Once when I re did the head and second one was 2 months ago. Idk what to do. I think the head gasket is made wrong. If you put that seal in there, at the edge at the head you can take a pick and go right through there. I can't remeber how it originaly looked but the head gasket was right or so I think when I pulled it. My local indie says its right but idk. To me it looks like that's why you would need a sealent in the corners. Well tommorow Im going to try again, wish me luck lol.