I only clean an eyepiece if it has gotten a fingerprint or eyelash oil. I used to use ethyl alcohol from a chemist and a cotton bud but now use isopropyl alcohol (99.9% from Jaycar; spray bottle, DO NOT use aerosol). Ethyl alcohol evaporated much quicker and also the chemist seemed hesitant selling it unless you had a good reason. (I’m talking late 1980’s early 90s).
Tele Vue suggest alcohol, acetone or Windex (latter for water soluble stain) for their eyepieces. See
https://www.televue.com/engine/TV3b_...=Advice&id=103
If using acetone it must be pure, ie not nail polish remover and you must adhere to IMPORTANT NOTE at last para which also applies to eyepieces with blackened lens edges, I.e. do not use acetone for these. See also third last para beginning with ‘Cleaning the edge’.
I have never tried acetone for risk of getting fluid around edges of eyepieces that do have blackened edges. Also don’t want to accidentally get some on the rubber eyecups.