Old, unmixed fixer - still good?

I've recently been given the dregs of some old darkrooms. As a result, I have a half dozen bottles, unopened, of various flavors of Kodak and Ilford fixer. They all have labels from a photo store that went out of business about a dozen years ago. I don't see an expiration date on any of the bottles. There's also one paper package of Kodak Acid Fixer.

I'd like to use these fixers for film. Of course I can mix a bottle and test with a piece of film leader to see if they will fix, but is there anything in these old fixers that might cause damage in the long run?
juan

sulfation..

Before you use one, mixed, or unmixed, in the case of the liquid ones, just pour them into another jug/tray/ etc before use, then sniff the empty container and look for yellow residue. If you find it, the fixer has had the sulfur come out of solution. I would stay clear of this stuff, and dump the lot on the idle flower bed out in the garden- it will love the ammonia. Once the sufation starts in a liquid fix I have never seen it stop.

On the dry fixes, mix them up. There may be a few yellow sulfur bits that form, but in this case I don't worry about them, because they are the result of individual crystals deteriorating, vs the whole lot being on the verge of dumping its sulfur. Others may hold different views, and dump any fixer showing sulfation.

Otherwise, do the usual how long does it take for the leader to claer, then double it to fix the film.

I just mixed up a dry package of 5l worth of agfacolor 60 fix from a late 70's bleach fix kit that the amm ferric edta was missing from. It still works fine, and fixes very quickly.

The test is very simple. mix a small sample of each and do a "film clearing test". If the solution clears film in less than 30 seconds, it is good to go!