A good friend of mine is having this problem. The disposal unit
behaved itself nicely for about six months; now it's jamming. She can
clear it, but it quickly jams again.

Any ideas? I know how to unjam a disposal unit with a wrench, but I
don't know what to do if it jams again, over and over.

Some background, for context:

--She rents, so removing the disposal unit is not an option.
Replacing it is an option if she can convince the landlord that it's
broken, but so far we're not convinced of that ourselves.

--She lives in another state. I can relay questions to her, which she
may or may not be able to answer. I can't go over and take a look --
at least not until the holidays, and she'd sure like to fix it before
then!