Rubber lens hoods are cheap enough to replace every 30 years whether they need to be or not. :0
Seriously, my hoods seem to last a very long time without any problems. When they shoiw signs of deterioration, I buy a new one for $10. At that price, a ten year rental is a buck a year, very low overhead I'd say.
I'll bet that solution is a petrolium based oil that will swell the rubber. If it stinks that much, I doubt you'd want to use it on your camera... ah that fresh outdoors aroma of the New Jersey Turnpike.