I spray a bit of WD40 onto a rag and wipe my rims down carefully. I avoid nipples,threads and-hook areas. Don't want to dry out any contact points that may result in breakage. I used to use degreasers and simple green stuffs. Had spoke problems. One builder told me wasn't good as it dries out the nipples making it tough to do adjustments down the line.
I wipe down mid sections of spokes, rims and brake surface. Brake surface is a lil squeaky (squeaky clean)for a while but after a mile or two, back to normal.