PMG (Paper Money Guarantee) appraised and slabs paper notes like this. Same company that does cards and comics (CGC). Basically you pay them money and mail them your bills and a bunch of dudes in a dark room verify it’s authenticity and grade it’s condition. Niche collectors thing.

Its similar to trading card grading if you’re familiar with that. You send it out to the company who inspects it, gives it a score and then seals it in a hard plastic container.

pmgnotes.com on a score of 35:

For years dealers and collectors called this grade “VF-XF.” This note looks Extremely Fine, but it will have four to seven light folds.

E: spelling