In uk.d-i-y, Martin Angove wrote:

Don't forget to put a little tape across PP3 terminals - they're close
enough together to cause a short if a bit of tinfoil or wire wool comes
into contact, and that, even if the battery is "flat", might start a
fire in your bin.

Or, indeed, succumb to the d-i-y obsession with not throwing *anything*
out In Case It'll Come In Useful by keeping the little plastic cap which
PP3s now ship with for the smaller terminal. I'm sad enough to keep hold
of mine and travel with them in place, when I carry a PP3 as backup
voltsource for both the mobile and the Palm. (As opposed to the two 12V
SLAs I hauled across the Glastonbury campus to keep all 4 family mobiles
on the go for the whole extended weekend... damn, they were heavy! but
useful).

Stefek