After removing a glued on patch I had to clean the old glue off. My first attempt was with Goo gone which didn't do anything. I then tried acetone, I didn't like the acetone because it was doing a really slow job with the glue, and I could see it was also dissolving the PVC tube material. I did some searching in the forum and found various threads and suggestions but they all had to do with Hypalon. But it helped me get an idea of what I needed; a solvent that will attack the glue but go easy on the PVC. I went to home depot and bought a few products.
1. Goof Off - It's supposed to be similar to Goo Gone, didn't do anything.
2. M.E.K. - It either didn't work or behaved like acetone, I can't remember which.
What caught my eye about this last product is that the consistency of my glue residue reminded me of the tile glue pictured on the can. It too was yellow and crusty, not at all sticky or flexible. I tried the Klean-Strip last because I thought it was going to be the most likely to damage the PVC. Anyways it did the job nicely. It has the consistency of gel and doesn't evaporate at all. I'd layer it on a little bit at a time and scrape off immediately. I was still concerned that it will eat the PVC so I'd work fast in small sections. But then I put some on the patch that came of and left it there for half an hour, there was no affect on the PVC patch. However some drops of it fell on some junk plastic shelving that I had laying around and I didn't bother to clean it, next time I looked at it the plastic turned into mush.
Some pics of the finished cleanup, and what the patch that came off was like. BTW can someone please tell me what this accessory is called so I can search for it? It's used to support the back of the tubes to the transom.