Dwight wrote:

I have a duffel of cordura material with a heavy YKK zipper - looks like
an aluminum slider

It is frozen, possibly as a result of salt water.

Is there any solvent that might work without destroying the fabric?

Thanks in advance.

Dwight
It won't destroy the fabric, but it might stain -- a silicon spray
used for lubing
aluminum sliding windows.

Maybe spray a lot into an old tin can, then use a
small artists' brush to apply right on the "slider" and the "track"
parts of the zipper,
working it into the area "under" the "sllder where it grips the "track",
on both
sides of the zipper.

You'll get better control of the application with a small artist's
type paint brush than you will with a spray nozzle.

HTH.