I have a ridiculous amount of bronze materials but like everyone else no silver mats. I think it would be fair to create a material trade store that can be used a limited amount of times per day or week if you want to be greedy. IE: trade 10 bronze for 1 silver material.

The unbalance of materials is a problem, there's no way to ever use up bronze materials with the current state of the game.

I've seen other games that require material grinding have trade stores to success.