Where would I go to buy a thin piece of mirror?
I would try a soft bristle brush and gently brush the felt and see what happens. Then vacuum without too much force, or use one of those sticky lint rollers to pick up loose particles. If there is actually a stain, try blotting it with a sponge, but don't use too much liquid. Great alternatives are a makeup sponge or a bit of foam rubber. Rubber sponges have a slight stickiness to them that will grab the stain off the felt. Again, rub the sponge over the stain in a circular, counter clockwise motion. Felt is difficult to clean once it has been stained.
You can't have different size gloves, this gives one an advantage. Both fighters get to train as much as they like in the buildup to the fight, if someone wears heavier gloves, they can seriously injure their opponent, even if the op is bigger.These rules are there to make boxing as fair as possible, if your hands are weaker naturally, tough luck, and if you don't like it, boxing is not for you. It's like saying, my opponent is bigger than me by 5 llbs so they should not be allowed to train for as long as me. ♠