I've got a 2001 and I don't know if this is the "right" way but the first time I washed them I got a $3 "wheel Cleaner" spray bottle at AutoZone and after a thorough jet spray from the hose to get all the sand and grit off of them, I applied the wheel cleaner and used a rag to finish up.
Now I just use soapy water and a rag. The wheels I have are easy to clean with your finger in a rag. This is what mine look like if you can see;
2001 Grand Marquis LS, 25K miles mint (edit; now 56K miles) Finally a vehicle with NO LEAKS !