Silicone based oil only. Bisley do some @ around £3.00 for a puny little bottle <img src="http://jsramsbottom.co.uk/bbs/e/icon_frown.gif" alt="Frown" width="15" height="15"><!--graemlin:--> but if used in conjunction with a silicone cloth it's fine and should last a while.
Does anyone know where I can get copious amounts of the stuff without paying through the nose?
Nev