My new KoAloha concert and my Kala tenor both have satin finishes. What's the best thing to use to clean them of fingerprints, grease marks, etc. (I have very oily skin, so I tend to leave marks on anything I touch...the CSI guys would love me!) I'm reluctant to use a "polish" as I don't want to turn the finish shiny. A soft cloth dampened with plain water works OK, but has trouble with oily residues. Would a drop or two of dish soap mixed with water cause any issues? Any other products or techniques that would work? TIA!