Lol, I have a set that have been sat in the garage for years.
They look amazing, but I know I can't justify the time needed to keep them sparkling
you need a decent, bare alloy safe wheel cleaner. Make sure it says suitable for bare alloy / polished wheels too (some have quite missleading names)
i never found the centres much of an issue, i found a sponge on a stick type thing which fitted through the gaps nicely. It's the polishing around each and every one of the 34 bolts per wheel that kills you fingers.
don't not do it though, as it won't take long until they pit or darken
and whatever you do, take them off before salt is put anywhere near the roads. it's literally impossible to keep them looking nice through winter. Think wash with soap and water after every journey, polish and seal once a week, even then you'll start seeing pitting.