ghs, non wax guitar gloss works well (not a spray) and martin and co guitar polish (this one is a spray). They have worked and never damaged my ukes. if you do get em, try it in a inconspicuous place first just to see if any harm will be done but i have never experienced any of such. oh yeah, dont use them of bare wood, and not on the fret board. looking all shinny in no time.