question about selenium toner

I've got a bottle of mixed/diluted selenium toner that's been sitting around for 15-20 years. Does it go bad and lose its usefulness?

Yes it does go bad but usually indicates this by throwing down a gray precipitate of selenium metal.

Thanks, Gerald!

Search for some of my posts on reusing and replenishing selenium toner. I have working solutions that have been going for more than 10 years. Just filter out the precipitate, replenish with a bit of stock to get the level of activity you need and you should be good to go.

That said, if your toner dilution was rather weak to start with and there's a definite precipitate, the amount of selenium in solution is probably next to nothing. Discard and start over if a test indicates no toning activity.

Doremus