clay doesnt clean off old wax for me. it may remove some part of it but if u have a good couple of layers of a selant it wont remove it. clay was designed to remove contaminants. not deisgned to level, shine, ect the finsh. only duty it has is to glide over the finsh and remove any particles that come along its way. the protection a wax finshed leave behind is soo thin that i dont think clay would be able to remove it. again, its main purpose is to remove contaminants that come in contact while rubbing it along the surface.
on occasions where i have had a really slick selant on my finsh and i decided iw anted to give it another detail, after i would clay, the finsh still felt pretty slick. when i would follow with a polish like ssr1 or #80, the finsh no longer felt slick, it felt smooth, but not slick, and when rubbed along the paint, my fingers would squeek!
the duty of the polish is to clean and at someitmes remove marr or swirls if the polish is strong enough.
my biggest misconception before i started detailing was that polishes add a lot of shine , the only way paint cleaning was possible was thru washing, waxes also added shine and protection, and once swirls were there the only way to remove them was a repaint or hiding them.
wash-remove grime dirt that has settle on the paint form driving, rain, ect.
clay-remove contaminants that keeps the paint from feeling smooth.
compound/polish-clean paint, remove OLD WAX, swirls/marr/scratches depending on the level of abrasives the compund/polish might have
glaze-cosmetic
sealant-cosmetic/protection
wax- cosmetic/protection
qd- cosmetic/slight protection
i may be missing a few explanations when it comes to those steps but thats sorta the general idea of wha they do. dont confuse them, and try to follow the basic order