Idiot King Inslee has decreed gyms may open, but its masks at all times. Unfortunately, my gym is enforcing it.

You can take one of those disposable masks and modify it. Its actually 3 distinct layers you can tease apart. Cut the inner two away cleanly, leaving only the outter blue one. Its 100% breathable.

You can tell, as its now semi transparant, but only if someone is close to you and looking. I have a normal mask for check in, and switch to the modified one after.

Need to try wearing two modified masks together, may be both breathable and fool proof.