I guess my thread title says it. The bike at issue has peeling decals and it looks ugly. What is good for removing them?

Depends if they were clear coated. In most cases, a plastic credit card or your fingernail will do. Then use Goo Gone to rub off the residual adhesive.

It might surprise you as being very easy. Take photos first, in case you want to find replacements later. You'll forget what they looked like.

imho.

Remove as much of the decal as possible mechanically...i.e. pull off as much as you can. Then use Goof Off or Goo Gone. I've used the Goof Off and it does an amazing job. Use the liquid, get some nitrile gloves to protect your hands and use it outside. It's not terribly toxic based on the MSDS but it does have a strong irritating odor.

stickers on clear plastic , are different from water transfer Decals.

so 1st figure out what you have ..

the above suggestions are OK with self adhesive stickers .

I've used a pretty powerful heatgun with mixed success. My 2014 BMX bike came with decals I didn't care for, so within 10 minutes I had them removed with heat. However, I am repainting an older kid's bike and the decals are putting up more of a fight.

Half way there using your method. It is a bit tedious. But the bike looks prettier.

It is yet another neighbor's bike and it is a Roadmaster. No need to ever get replacements.

NO! Bikes are not pretty! Girls yes, bikes, tractors, cars, trucks, NO!

Bikes can look sharp, awesome, or cool.

After removing to layer sticker decals recently, I was able to get the residual glue off with some alcohol swabs (like you use to sterilize a medical injection site) and a little elbow grease. I think my wife's finger nail polish remover (acetone or ethyl acetate) would have been a better solvent, but she wasn't home and I couldn't find it.

Try a hair dryer, it will heat up the sticker enough to make it sticky again and won't damage the paint like a paint removing heat gun.

3M and a few other companies make rubber wheels that go on a power drill or grinder that are specifically made for removing applied decals without damaging paint. You can get one at any store that sells auto finishing supplies. The good ones create enough friction to warm the decal loosening it and then strip it away in small bits. It can be a bit tedious working on the tubes of a bike as it was designed for use on cars and trucks with larger, flatter surfaces. Goof Off will work for those areas that can't be reached with the disc and for a final wipedown to remove residue.

If you remove decals on an older bike, the paint underneath may no longer match due to fading and etching of the surrounding paint. Sometimes you can fix this with rubbing compound followed by a polishing compound. Sometimes that isn't enough and you have to either live with it or redo the paint job.

I left my hair dryer back in the 80s.

I'd try an orange-oil cleaner, such as De-Solv-It first. It has worked better than the petroleum-distillate products mentioned for me and isn't toxic. There's a lot of worthless stuff that contains just enough orange oil for scent, not enough to dissolve anything.