Cleaning taillight lenses

I bought some Duster taillight lenses at the Nats that were all goobed up with some sort of black tar-like substance around the edges. Apparently someone in the past had tried to seal a trunk leak. I was able to get most of it off just by pulling it off but there is some left that is smeared on the lenses. I would like to know if anyone can recommend what I could use to clean it off that won't tarnish or otherwise harm the plastic lenses. Thanks.

Some common paint thinner may help. After, I have found that common polishing compound works quite well on plastic lenses. I start with the polishing compound then use the plastic sealer in the Eastwood plastic polishing kit to finish.

mothers mag wheel polish works well

I would caution using any solvent such as paint thinner on plastic, it likely will damage the plastic..

Just my $0.02...

Use an Orange Citrus cleaner to get off the goo

Pledge liquid or spray furnish polish works very well on Lexan airplanes windows
I've used it on several old faded tail lights and they look a lot better now than before

some plain old kerosene or wd-40 might also work. i believe neither will damage the plastic.

Toothpaste is soft enough even to get lense polished.

Stock lenses won't be damaged by thiner or kerosene. Can't talk about repros. I'd try kerosene since won't evaporate inmediatly. Then finish the cleaning with toothpaste

Try Bonami cleanser. It works. or Flitz polish