I have a few accessories that use these batteries, but I hate leaving them in there during storage. Just tossing them in the box can be a problem with shorting. So I made these simple caps. They fit snug enough not to fall off. If there's any snots or bumps inside, clean them out - or the cap may be too tight. Change the scale and make caps for any size battery.
Take about 8 minutes each to print @50mm.
The author hasn't provided the model origin yet.