Thanks gents, looks like they will accept most regular stuff then? I will look up some suitable brown stuff for them maybe try that protective spray. I noticed in local market some cream (or 'grease') type product some of which seem to contain beeswax and they're mostly colourless, so not like your regular polish. Maybe these would do the trick?
"A prudent man should always follow in the path trodden by great men and imitate those who are most excellent, so that if he does not attain to their greatness, at any rate he will get some tinge of it."
— Niccolò Machiavelli (Prince)