I been using carsoap and water only to wash my rims. I was wondering is it safe to use a sponge on the lip?

 

I personally use a brush and mitt to wash the lips. I don't see why you would not be able to use a sponge as long as you're taking the proper precautions to rinse the dirt out. If your wheels are grimy use a two bucket method on your wheels.

 

whoops I forgot one thing. I like pre treating my wheels before going at it with a brush or mitt. Pre treating will loosen the dirt.

I pre treat loosen then rise. If it's still caked on repeat the process until satisfactory then light use a brush and mitt to remove the remaining grime.

Hope this helps.