If they are binding they do not simply need Copper Grease. They need dismantling and cleaning out thoroughly then reassembling checking that all components move freely.

As others have said, unless you absolutely have to improvise, its safer not to.

Copper-based antiseize is very difficult to find here in Taiwan, though I now know a place in the next city where I could buy a kg tub of it, which would last me until the heat death of the universe.

That said, aluminium is a pretty good (in fact, possibly superior) substitute for copper in this application, and widely available.

The top of a coke can, cut off, gives you a clean up tool which can be used for scraping off corrosion. If you've got some small rusted threaded parts to clean up, you can rattle them around in the ring-pull hole.

Finish-off rubbing with aluminium foil. These "treatments" will leave some dry aluminium on the surface which will have some anti-seize/anticorrosion effect.

Making anti-seize grease is a bit more dodgy, since it requires the base-grease to have the right properties.

I make aluminium-based antiseize (which I've never seen here) as follows. Put a tiny dab of your grease of choice (I usually use lithium-based bearing grease, but note that this is not rubber-compatible) in the base dimple of an (empty, or at least unopened) beer or soft drinks can.

This is your mortar

Roll up a wee ball of aluminium foil, the finer the better.

This is your pestle

Rub the pestle around in the mortar until the grease looks dark gray enough. Then scoop it out with your finger and apply.

If you don't want to get your finger dirty, wear gloves (or use a plastic bag) but you were probably doing that already, you big Jessie.

I havn't so far located a source of rubber-compatible grease here. I have used ear-wax in a pinch, but of course its only available in rather small quantities at any given time.

Copper grease in French is "Graisse cuivre" - you can get it online from places

like :-

www.oscaro.com/graisse-10132-gu

or www.mister-auto.com