Looking for 10" bamboo steamer that will last!
Normally in the trade, we don't "hand wash" the bamboo steamers, we just let it sit in hot water for a bit and rinse it off. Try not to scrub it either.

Obviously, most of us aren't steaming things on a commercial scale, so I recommend placing a sheet of either baking, parchment or butter paper below the food when you steam. The sheet acts as a protective layer, preventing food from sticking to the bottom and prevents the steamer from getting too dirty (stuck bits of food, etc)  which also makes cleaning easier as you only discard the sheet. You don't need to change it after every item steamed, only when you feel its necessary