Humm, I had a half gallon bottle (brown plastic, stored in dark, mostly full) if 1+19 and it no longer tones at all, and had all manner of crud floating it in it. Dumped and about to remix.
Well when I say "dumped" I mean into my "selenium bucket." I dump used toner into a bucket reserved for that purpose and let it evaporate. The selenium will be left. Eventually the bucket can be taken to a hazmat disposal. In the meantime, it avoids putting it into the environment.