I picked up a old fridgedaire from a guy that picked it up from a storage unit. This smoker was setup as a propane setup. I converted it to a charcoal/wood setup with burner directly underneath the cook chamber. There is a black silicone type material around the seams. Can't tell if the guy who built it put it in. Or it came factory like that. I have scraped alot of it out. Wondering if it would be ok. I've had it up to about 350deg and no funny odors or anything. Wondering whether to sand blast it. Also curious if anybody knows what I can insulate the inside without doing a second wall.