I just pour some into the silicone rubber seal thing and slosh it around. then rinse it. That poor thing gets grungy.I just use vinegar full strength too - it's cheap enough and rinses well. Some tanks just have hard deposits that needs a good soaking with full strength vinegar.
Hydrogen peroxide is safe enough to use too - that also rinses well. I would prefer that to bleach when I can. Mark Brown - How would you use that on a cpap mask?