How do I refurbish an old mirror - should I spray paint the back?

What seems the problem with the mirror?

If the silver has worn off and you have dark spots on your mirror, this link has some ideas for you:

https://abeautifulmess.com/2015/10/4-soloutions-for-dark-spots-on-vintage-mirrors.html

I would consider embracing its “age wrinkles” as the mirror “spray paint” can’t produce the quality that factory manufacturers do, assuming this is an old mirror.

I found this article on re-silvering an old mirror, I hope it helps: https://angelgilding.com/re-silvering-old-mirrors

https://youtu.be/p2vennxCTbY

Considering the working time and expense and possible frustration of trying to restore the mirror, I would just replace it. If the piece is an antique which is worth some money, just leave it alone. Apparently, the value reduces if it is replaced.

I refurbished one using mirror effect spray here are the results.

https://uniquecreationsbyanita.com/tips-for-restoring-an-antique-dressing-table/

Don't spray paint the back You need to strip the paint and silvering.Use Citristrip Stripper. Then you can spray with mirror paint.

https://www.hometalk.com/diy/decorate/mirror/turn-glass-into-mirrors-29461033

https://www.hometalk.com/diy/decorate/mirror/how-to-make-a-mirror-with-mirror-paint-5719847