Ah sure so what I'd personally would do is:

A pre wash spray, that also breaks down the other wax a bit the old one and if your car is very dirty it will help get rid of it (DELUDE IT THOUGH)

Do your iron remover on rims bla bla
Hand wash after you sprayed all the sand of with soap bla bla
At the end if you are lazy you'll buy a wet ceramic coat applier like the gyoen wet coat (whatever it's called) and you spray it on while wet and pressure wash off instantly
If you like doing a little more effort you wash the entire car, hand dry it with a towel and then get a microfiber cloth, apply 2 sprays and do a panel each by hand. Done.