Nishasmom....leathers collars can get wet if protected with a good heavy duty water repellent. I use one called dubbin. I got it here:
Leather Dyes, Neatsfoot Oil, Leather Polishes, Dubbin, Cleaners
it is inexpensive....whe wesite is canadian, but they ship to the US. However, a quick google search turned up results for various shoe/shoe repair stores if you want to start looking in your area.