Anyone know what this is and how to remove it?

[Nicko]

I found this stuff under the improperly mounted and leaky awning on my recently acquired 1973 Trillium 1300 which I believe to be some type of silicone. Anyone know how to get this stuff off??? I've made almost no progress trying to use combinations of a heat gun, pliers to pull at it, plastic putty scraper to try and get under it, etc. It just does not want to let go of the body.

The only thing I haven't really tried is some type of solvents, but I'm still not 100% sure what it is I'm dealing with. I've attached a link to a video of this stuff and a few screenshots from that same video. Hopefully someone has some ideas. Thanks all!

https://vimeo.com/1083164559

[Nicko]

Well, whatever it was I managed to get it all off. Plastic putty scrapper, dish sponge, goo-gone, and a hell of a lot of elbow grease. 3.5 hours later it was clean.

[ThomasE]

That's plain old silicone caulking and it's a lot of work remove completely. I've used a single edge razor blade scraper to remove most of it followed by a non-scratch scotch brite pad and goo gone.

[Iowa Dave]

I have a set of four red plastic chisels for body work from Harbor Freight. They were $10 when I bought them in 2013. Probably a little more now. They are 1/2, 3/4, 1 and 1 1/2 inches wide I think they work well on old silicone. If they get dull I sharpen them with a mill bastard file. I just keep one in the camper tool box and the others stay home.
Iowa Dave