Beautiful looking JP-6 there Carey. The sort of glossy (personally I would call it more like Satin) finish looks like it is the same as from factory, as mine has same sort of finish. And the colours and screen print all look original. Does it have the Europa Modification Kit. If not I totally recommend you look into that as it adds a whole extra bunch of features and enhancements to the JP6, so definitely worth doing. www.synthcom.com
Generally the Jupiter 6 is usually found in much better condition nowadays since they weren't used quite so much when touring or in live situations, and tended rather to be studio based. Unlike the Jupiter 8 which was used live and therefore thrashed about by just about everyone back in the day, so finding an original Jupiter 8 in exceptional condition that hasnt been restored to some extent is quite hard. At least that is how it seems to me, but feel free to disagree anyone.
p teck, to clean the caps on your JP-6, I take it you mean the plastic tops from the pots and sliders. If they are really filthy then I would take them off and let them soak for a while in some soapy water (a bowl of luke warm water and washing up liquid works well here). Then use a soft brush like an old toothbrush for example and gently brush along the dirty grooves of the caps. I think sugar soap may be too harsh on the plastic and could damage the caps. I have had to clean caps and other similar items before and none of them needed anything more than just a gentle scrub with some water and washing up liquid. And make sure the caps are thoroughly dry before putting them back so water doesnt drip down the pots or sliders and on to the boards.
Hope that helps.