Help with decal removal

[TKModder421[TK]]

So I've got an ANOVOS bucket I've been modding and I was doing a little clean up on my frown paint job. Of course I didn't take the necessary precautions of taping things off and unfortunately I got a small drop of testors paint thinner on the tube strip decal, it immediately smudged like it was fresh paint. So I cleaned up my mess and removed the stripes that had been smudged. I continued working on the frown with the intent of fixing the tube stripes later. So I finally decided to buy new decals and now that it's been over a month I decided to finish the job. But now for some reason, the  paint thinner doesn't have any effect on the remaining section of the decal. I've been searching for 2 weeks now for any ideas on how to get the decal off without using a caustic chemical that might damage the plastic or sanding (I'm trying to avoid doing so). So far I've tried Testors enamel thinner, rubbing alcohol and Purple Power and none of them has had any effect on it! I don't understand. I've seen threads that showed modifications to buckets where all the paint and decals have been stripped, I've asked in responses what they've used but I have yet to get a response. Does anyone have any suggestions?

[Harbinger[IPM]]

Have you tried full-strength rubbing alcohol? The grocery store brands are usually not as potent.

[themaninthesuitcase[Admin]]

The tube stripes on mine were removed using Humbrol enamel thinners.  They pretty much just wiped off!

[TKModder421[TK]]

16 hours ago, Harbinger said:

Have you tried full-strength rubbing alcohol? The grocery store brands are usually not as potent.

I have not. I'll definitely give that a try

[TKModder421[TK]]

6 hours ago, themaninthesuitcase said:

The tube stripes on mine were removed using Humbrol enamel thinners.  They pretty much just wiped off!

That's how they acted the first time the Testors thinner touched it, but now it has no effect. I'm baffled! Maybe I'll see if I can get a hold of some Humbrol thinner and give that a try. Thank you!

[TKModder421[TK]]

So I went and bought a new bottle of the Testors thinner and it worked great. Wiped right off.

I decided to pick up a new bottle because I had been calling local hobby stores today trying to find the Humbrol thinner and I ended up talking to an employee who clued me in asking how long I'd had my thinner, saying sometimes if it sits on a shelf for a long time it could lose its potency but I told him it worked great just 6 weeks before. He said the stripping chemical (diluted acetone maybe?) that's in the thinner can evaporate over time in a sealed jar, but not in 6 weeks. So I'm thinking I must have left the jar open overnight or didn't tighten the lid or something because apparently my original bottle has lost its potency.

Thanks for your input Brien and Chris, I really appreciate it!!