Plastic battery cap keeps falling off

[Figurehead]

My 901 batteries (2 of them) keep losing the little plastic cap. I want to glue them back on but don't want to damage the battery. Is this possible using as little glue as needed? also, it really doesn't hurt anything if the cap is not there does it?

 

[dnakr]

I used super glue to fix mine. I went around the edge of the cap very carefully and it did not hurt anything.

 

[invidregis]

Don't block the 2 little cutouts on the cap. The need to be there for airflow, otherwise the switch wont activate. Just glue around them.