Name: Ed
Message: Dear Paula-
I purchased some materials (Dyes, synthrapol SP, dye fixer, urea, ludigol) about ten years ago of which some are unused. Has any of it gone bad or can I still use it?
Thanks.

The dye fixer, which is soda ash, will stay good indefinitely, but may absorb up to twice its weight in water from the air, which would mean that you need to measure out three times as much as you would if it were still anhydrous.

The urea is still good unless it smells badly of ammonia; urea naturally turns into ammonia given enough time, or the right microbial contamination. I believe that it's probably okay to use even when slightly contaminated with ammonia, but not if it is unpleasant to have open in front of you.

I would shake up the Synthrapol SP, and try using it only if it looks okay and does not have an odd smell.

I have no idea whether or not ludigol goes bad. It's useful to prevent reduction of the dyes during steaming or microwaving, but is not required for room temperature dyeing.

Fiber reactive dyes, however, do go bad, with time, by reacting with the moisture in the air. They can still be used as acid dyes, with vinegar or citric acid, for protein fibers such as silk or wool (as well as nylon, but no other synthetic), but if they have gone bad, they will no longer react with cotton or other plant fibers to form a permanent chemical bond. The shelf life advised by the retailers is up to one year, stored in a cool, dry place with tight lids. I personally have dyed successfully with fiber reactive dyes that are several years old, using a bit more dye to make up for any losses, but have never tried dyes as old as ten years. You may do best to save these dyes for use in acid dyeing. ProChem has a good recipe for dyeing wool with Procion MX type dyes, with the necessary heat-setting being done in a black garbage bag.