Chlorinated hydrocarbons like trichlorethylene, which I have used in carb and brake cleaners will attack some plastics like polycarbonate (Lexan).

Aliphatic hydrocarbons like mineral spirits, Varsol, naptha ususally will not harm most plastics, but will attack silicone rubber.

Aromatic hydrocarbons like acetone, tolulene, and MEK attack most plastics except polyethylene and teflon.

Most alcohols are safe to use with most plastics, but attack some rubbers.

The safest cleaner would be the fuel that is used with the carb. I use Coleman camp fuel which is basically like naptha for my gas carbs, and speed shop methanol for my glow carbs. I use both, with oils added, as fuel also.

Good luck.

Sincerely, SPACEWORM, Saito Club #635