[It has been a VERY long time since I've worked in the darkroom.] I'd toss it. Your time is much more valuable that the few dollars you may save. Stains!. That being said, B&W home development has REALLY gotten expensive! The chemicals and paper are pricey. And where do you throw away the used chemicals, [in the "good old days," we'd just chuck them down the toilet; 'prolly not a good idea now...].