I have pretty small hands and I can't reach through anything on these wheels....
Either way, for a quick clean I just use the daytona brush with SONAX, it gets most of the stuff off. If I am really getting down and cleaning them up/waxing them, I take the wheels off completely.
'11 BMW E92 ///M3 - ZCP and DCT
'15 Ford F-250 - Lariat, 6.7 Powerstroke Turbo-diesel