Whats the best way to remove a self-stick type decal/sticker off some iron on covering. I know there is stuff called 'stickeroff' available at hardware stores, just don't know how it would affect the covering. Thanks in advance for any ideas.

I have done this: get one edge of the decal lifted slightly and start wicking denatured alcohol under it. Keep wicking the alcohol under it as you gently lift and pull as the alcohol releases the adhesive. Once the decal is removed go over the area with denatured alcohol on a rag to remove the adhesive residue. The downside is the decal can't be used again.

Add heat. The glue will soften and the decal will come up.
Then use alcohol to remove the glue residue

Lacquer thinner works better than alcohol if the thinner won't harm the finish. Films aren't bothered by lacquer thinnner, but many paints are. I also use lacquer thinner to wipe up the excess glue that oozes out around seams. Makes the finished plane look a lot better.