Urinal cakes are made of paradichlorobenzene (at least
most of them
are) which is the same material from which mothballs are made. It soaks
up odor, but it doesn't "freshen" or scent the air, usually.
My experience with mothballs, and this could be rather dated,
is that they leave their own unpleasant odor. I've had the
displeasure of unpacking stuff that had been packed with mothballs
for long periods of time, as in quite a number of years.
Jeff
--
Collector of Classic Microcomputers and Video Game Systems:
Home of the TRS-80 Model 2000 FAQ File
http://www.geocities.com/siliconvalley/lakes/6757