If your gonna up em upside down to stop dust getting inside you need a spindle or something (to leave an air gap) - otherwise they get musty inside and start to smell and you have to wash them a couple of times anyhow...
So we always put ours normal way up - they don't stay there long enough usually to get dusty inside anyhow and if they did they'd need washing anyhow (musty smell).
So we always put ours normal way up - they don't stay there long enough usually to get dusty inside anyhow and if they did they'd need washing anyhow (musty smell).