Hey smiley.
Not a stupid question, quite a common one!
There are a few options out there. Firstly there is a product called wheel wax. Its designed for this purpose and is designed to withstand the high temps.
The next option is to use a sealant like Zaino. I pretty much always do this when i do a car as there is always a bit left over.
The third option is to use whatever wax your putting on your paint on there. Its safe as the rims are probably clear coated anyway. This may last ok or durability may be very bad depending on the wax. I know for a fact optimum car wax (OCW) lasts at least 3 weeks at which point you should have washed and waxed the car again lol



