On Tue, 19 Sep 2017 14:41:08 -0500, CRNG wrote:

I've used 90w gear oil new from the bottle. I would be hesitant to
use _used_ oil from anywhere because it might contain particles that
could clog the chain oil delivery system.

Thanks for letting me know that 90 weight gear oil can work, if new from
the bottle. The Red Line MT-90 is about 20 bucks a quart so I wouldn't use
that.

I understand your point about the particles, which definitely were in the
magnetic trap. I guess I could "filter" out the bigger particles, but your
point is valid that almost certainly there are myriad small particles in
used gear oil.

I think your suggestion that the particles would be bad for the chain is a
good enough reason to just throw the used oil out (to Jiffy Lube) and waste
it.