Originally Posted by TONTOROSS
I used heat-gun, scrapped off the lettering, then used a 3M adhesive remover to get the glue off. I used a clean white cloth for that part. I then wet sanded using 800 grit followed with 1000 grit. When completed, no evidence the previous name/numbers. Worked great. Our boat had a name that took up a lot of space, both on the bow & stern.
Sounds like a decal removal not a painted on as the OP has described he has??
I tried the oven cleaner but would not take off the 30 some year old paint that was on my transom. I ended up using a razor blade at low angle and slowly got it off. Followed up with wet sanding. Covered over the whole thing with a decal with a border. There was just too much difference between the two surfaces to mask. Good luck!