Just like the age-old debate on who was the coolest Beatle, people can't seem to agree on whether it's better to just go out and buy car soap or make it at home. However, for every person who says dishwashing detergent will strip away wax and paint, there is another who says homemade car soap made with dishsoap is a safe alternative to store-bought car soap.
Find the best detergent (the sudsier, the better). Cost, brand loyalty and other intended uses are also things to consider. For some reason, Ivory is popular among car professionals who are in favour of homemade car soap. Also, if you are allergic to any cosmetic scent or colouring, find the blandest product on the shelves. Environmentalists may consider nontoxic and biodegradable versions of the soap, since the soapy water will be seeping into the ground, thus affecting the area's habitat.
Find a bucket. Depending on the distance from the water source to the vehicle, you may want a smaller or larger bucket.
Fill the bucket up with water. If you live in an apartment complex, find out if there are water outlets at the ground level. If not, water will have to be transported from the apartment to the car. If living in a house, pay attention to city ordinances on water usage. Car washing may be restricted to certain times of the day in times of drought, and it may be advisable to avoid using water hoses altogether.
Combine soap and water. The ratio of dishwashing soap to water isn't an exact science, but start with approximately 1 tbsp of soap to 2 gallons of warm water.
Do not fear of paint being stripped. Also, wash the vehicle before waxing it. Although dishsoap does break away car wax, proponents of dishwashing soap say that this is not detrimental to the car.