Help ID Cloisonne bulb dish - copper base

Can anyone tell me anything about this bulb dish. It's copper with cloisonne. I can't seem to find anything quite like it. 12" across. Very heavy. Is it a bulb dish or was it the base for a plant pot?

 

Doesn't look to have much depth. How deep is it?

 

2" deep. That's why I thought it was a bulb dish, but would you just put water in it without a liner? If it's copper, I guess you might. Also, should we try to clean it? It was inherited by someone and they wanted to know about it and I'm not overly familiar with cloisonne.

 

I always put pebbles in a bulb dish and the bulbs sitting on top of that. Mine are about 2 inches, but they're much narrower. At 12" across I would be more inclined to use as a saucer for a pot, although that's just me. If you want an abundance of blooms, 12 inches would sure give you a lot!

I don't know what to recommend for cleaning the enamel part. I'd leave the copper alone.

 

I'm hoping one of our Asian experts can tell me about the mark. I may have it upside down.

 

Don't touch the copper. Best bet on the closoinne is a Sunshine Cloth.