Fuel Filler Cap Corrosion

[fozzy]

The fuel filler for my underfloor tank is an alloy of some description, and while it doesn't show any powdery corrosion or whatever, it's starting to become difficult to open.

It sort of "binds" and is hard to turn. Is there some sort of lubricant I can put on the threads so that I can undo it easily that won't go gummy if it comes in contact with fuel or whatever?

Thanks,

Dave

[finga]

If it was mine...
I'd be taking the cap off and give it a good going over with a stainless wire brush.
I'd then give the internal thread a wipe with a stainless scourer (from the supermarket) as they have big chucks of stainless which would have less chance of bits going down the plug hole.
Then a wipe with a clean rag with either some fuel or solvent cleaner to get all the residual crap out.
Is there an O-ring in the cap??
If so I'd bung a tiny bit of silicon grease around it.

[Roughasguts]

Hmmm come to think of it mine is a bit stiff and locks up every 1/2 turn or so.
Might put some silicone spray on it now see what happens.