I did find some info on the American LongRifle Forum about a member asking the same thing as I, shelf life. Some other info I found on the web also. All the answers ranged pretty much as bubba.50 advised to try it out and see. Several other's advised of using both AF and tru-brown some 12 years old with same results as newly bought. I did call several large US suppliers of the products and they advised as long as it has been out of extreme heat/cold and kept out of sunlight and sealed good, it should have no problem. One supplier advised if it is in plastic bottles, there could be some acid to plastic reaction. Mine are both in glass bottles, don't know if they come in plastic now or not. I couldn't find any website or phone number of the maker 'Waukon Bay Outfitters', but one of the suppliers advised they know of the people running it, but no contact info. I'll just have to try and see how it does work. I'll report back on the results when I get around to using it, thumbs up or thumbs down!!!!