Usually if it has been washed ...it has been pressed...
There are alot notes that are processed in different ways... You can buy them every day of the week on famous auctions sites..This year I have sent back notes 5 times because of processing...
When you see an advertisement on TV or where ever "Collectors notes" Museum Quality notes" all sorts of phrases to obfuscate the true quality of the note...run
So if it smells like a chemical , baby powder, bounce sheets, ozone etc someone is up to no good.
Your best indication is feel the note and look for the embossing...if your unsure get yourself a genuine unc note and examine it carefully by touch and sight..you soon will be able to spot the funny money..unless of coarse you like funny money..then there is lots to had....