I've used them for years - but not for long periods. I'll put used paper developer and fixer in them that I know I'll use within a few days or up to a week. If I anticipate longer than a week or so I dump the chems; similarly, if it's much longer than a week when I get back to them I just dump them and re-mix a working strength batch. I've used the same Falcon ones for 25 years or so now and haven't had any issues. That said I don't use them for long-term storage.

Bob H