To polish your wee uke, it’s recommended you use a clean, soft cloth to wipe down the entire instrument. Oil from your skin takes its toll over time and keeping gunk for building up will save your finish. For a deep clean every now and then you could try out some official ‘instrument polish’. Lots of people also rub some lemon oil into the fret board to completely spiff it up. (Dunlop Fretboard 65 Ultimate Lemon Oil etc, etc, blah di blah).
You can of course choose to keep people from Poland clean as well if you like, but they are probably already really good at keeping up with that sort of thing on their own. And might look at you oddly if you suddenly started cleaning them. Probably best stick to your uke.
Although, a gloriously lemon scented Polish person…thumbs up!