DEAR LIST, I have a rather large pile of thin paper coated with the proper albumen mix (Ammonium Chloride, egg white, etc.) but not yet coated with the Silver Nitrate. It worked very well when new. It is rather old...perhaps 5 or more years. Of course I will try it out but does anyone have any experience with this who can tell me whether it would "go bad" or should be O.K.? CHEERS! BOB