1.Use two buckets instead of one
One for clean water, one for rinsing all the crap out of your sponge or wash mitt. Simple.
2.Don’t use household cleaners or dish soap on your paintwork
Fairy Liquid does a great job of cleaning your dishes and it smells lemony fresh too. It’ll also do wonders at stripping the wax and polish off your car and then eating away at the clearcoat. Houshold cleaners can either be very acidic or very alkaline, and that’s A Bad Thing for your car’s paintwork. Get a proper PH-neutral car shampoo.
3.Get rid of the big stuff using specialist products
It doesn’t matter how much you wash, the hard stuff like road tar needs a specialist product, especially if you’re looking for how to remove tree sap from a car.
4.Bring microfibre cloths – lots of them
Simple enough really. They do the job and wash up well afterwards.
5.If you live in a hard water area, don’t clean your car on a 40°C day
the soap and water will dry out and cover your car in calcium streaks quicker than you’ll ever be able to rinse it off. If you must do it, buy a popup portable awning and do it in the shade. You’ll at least have some chance. Frankly I’d wait for a cloudy but dry day myself.