All Ritchies use Odorless Mineral Spirits, HFG. Get it at any drug or paint store.<br /><br />Don't know what brand might use glycerin.<br /><br />Moving to boats.
My bad, JB is correct. Glycerin is used in water speedos and some gauges to dampen the pointer fluctuation during vibration, so I assumed (there's that word again) that it would be the same in compasses.
Take a drop of the existing fluid out and drop it onto newspaper. Leave it for an hour or two, if it evaporates it is an alcohol/spirit based fluid and if the stain is still apparent and makes the paper appear slightly translucent it is probably oil based. Make sure you don't mix the wrong fluid as a top up otherwise it is likely to go milky. If it is alcholol based I have heard of using neat gin as a top up if you cannot get the clear alchohol.
