Vintage Brass Crystal 5 lights Chandelier with 6 foot chain and mounting

This beautiful vintage brass chandelier has 5 lights with 50 crystals, 6 foot chain including a mounting. I purchased this at an estate sale to place in my main floor bathroom. It's about 2 feet wide and 15 inches high. It has a pineapple shape to it, which I have heard means "welcome."

I don't know any of the history, but it came from an estate sale in Detroit, MI. I would like to know if anyone can tell me any information about what period of time this is from, or how old it could be, or what markings I should look for, if any. It doesn't stick to a magnet and it is very heavy. My guess is that it may weigh up to 30 lbs.

Also, I haven't cleaned it yet. However, if it is really old, how should I clean it? Does cleaning this with a commercial product devalue it in any way?

Thanks for any feedback.