TOPIC:

How about the spray that's used to condition 1:1 tyres?
I think there's silicon (edit : it's alkoxysilane) in that also... and some other active components.
Should help with giving it a nice colour too.
You'd have no grip at all when trying to drive though...

I used to boil brake calipers in water (To get them to bits, bike resto projects) & noticed this used to make the seals much more pliable (Even when dry & cool), but I don't know if the effect would last. Similarly, whilst getting the glued tyres off the rims of my TXT, by the advised method of soaking in cellulose thinners (Doesn't really work that well on CA glue as far as I could see, even after 12hrs, by which time I was fearing for the damage the thinners could be causing to the organic based components) I noticed they felt a lot more "rubbery" (They swelled too, but the swelling went down after a couple of hours), they still feel ok a year later, & loads better than when I got them. I would think any mothod would be dependent on what type of rubber is being treated & how far gone it was to begin with. I would say anything heat, solvent or oil based is going to hurt natural rubbers. As far as being allergic to latex goes, are you sure it's not the spermicide playing you up?!

I have stumbled over several postings with the same question, on these topic the use of peanut butter or peanut oil is mentioned, apparently this works pretty ok because the oil/grease is a natural one thats compatible with the oils in the tires rubber.