Matte finishes are a bad idea because repeated rubbing with a cleaning rag will turn the matte finish shiny. I'd try mineral spirits, applied gently with a soft cloth or paper shop towel to remove grease. After that, a moist microfiber cloth may be sufficient to remove ordinary dust and dirt.
If I ever find a frame I just had to have with a matte finish, I'd scuff the whole thing with grey scotchbrite and give it 3 coats of gloss urethane before building it up.
Last edited by DaveSSS; 07-05-19 at 01:48 PM.