Having a heck of a time cleaning the whitewalls on my anniversary FLHRCI. Anyone got good tips on getting whitewalls clean?

Many thanks.
I'll let you into my trade secret for this.

I'm always asked how I keep the whitewalls so white and clean, and the answer is what I call "the Wonder Stuff"! It cleans whitewalls beautifully, it makes the black bits of tyres black, it takes tar spots off wheels, mufflers and headers, it dries quickly by itself - and mixed with washing up liquid it makes a great hand cleaner (but you need to moisturise after!)...... It's cheap, and most houses have it! What is it? Well, here's the problem - I don't know what you call it in the US! Here we call it "White Spirit" (years ago it was always labelled "turpentine substitute" too), but it's the stuff you use to thin household oil-based paints and clean paint brushes. I buy 2 litre containers of it, lasts a year, and is an indispensible aid for detailing the bike. But it's best use of all is cleaning whitewalls!

Jim