Painted Glass Tetra How Do I Clean Nicotine From A 50 To 70's Era Hanging Hand Painted Glass Lamp?

How do I clean nicotine from a 50 to 70's era hanging hand painted glass lamp? - painted glass tetra

I recently inherited trailer, which is 50 to 70 AD. People who have inherited, were heavy smokers for years, and therefore the lamp is covered with nicotine. I'm not sure what I can use on him, not damage the paint. It is a kind of iridescent hand-painted roses on it