As James said I generally give the whole car another very quick wash after iron x and tar remover.
Literally the best stuff I’ve ever used. I replaced everything on my shelf with their products. They do a starter pack on the site for £50 that has everything except ‘purge’ which is their version of iron-x. It shifted stuff off my wheels that nothing else would touch. Use the code RMS10 for 10% off. I think it’s free delivery too.
I know the owner through a local car forum and he’s a really solid guy and his customer service is second to none.