Just pulling my steering pedestal apart to replace the bearings. Tough job. Lucky I have a very helpful neighbour with a great workshop. In between the bronze gears there is a lot of grease with a greenish tinge. Mounds of it. My neighbour thinks it's copper grease. Has anyone done this before and can recommend a grease or lubricant for the mesh gears? Given the gears are not accessible without a lot of effort there will not be a chance for reapplication.

That really looks like they've used something like penriteoil.com.au/products/white-grease

The discolouration is just age.

Use anything that is suitable for bronze, as that's what those gears look like, and that is waterproof if it's likely to get wet.