Tardis is the best stuff ive ever used.
Its a bit annoying, but the best way i found to use it was to wash your car first, your usual wash method, dry it off, then using a chemical resistant bottle,( it will eat through spray heads) spray mist the tardis on each pannell, one at a time, working your way up lightly misting the pannell, dont soak, and dont go as far as your window rubber. you should see the tar starting to run down the car, then mist a soft cotton cloth and lightly wipe the tar off your car.white is best so you can see whats coming off. DONT apply any pressure, you could damage your top coat. Tar has micro grit in it so be careful.
if you need to, for heavier tar deposits, reapply tardis, wait a little longer and same process. never rub hard, you've been warned !!
Dont forget to rinse your car off after too, best bet, blast of snow foam, then rinse and dry. The Tardis can stain if you leave it dry on a hot day, not that we get many !!!! Tardis is water soluable so will run off.
Tardis will pretty much strip your wax protection too so dont forget to give a quick rub of polish, and reapply your wax or sealant.
Padraic