ive used a leaky unicolor drum for years ( on and off )
and when i purchased the roller and drums i contacted unicolor ( they were still around )
and they told me it was in the instructions to smear a tiny bit of vaseline
on the thin gaskets to keep them sealed ... ive been using it like that
never a problem with contamination &c .. i figured
if the company that made the tanks had it in their instructions
it probably isn't bad ...