Personally, I think that if you care at all about the condition of your car, you should buy some minimal supplies rather than using items around the house. I've seen people use diswashing liquid on their cars, but I WOULD NEVER do that on mine. I do not recommend this. You could probably get sufficient products for washing your vehicle for around $10 (if you're going cheap). You could buy a generic bottle of auto wash for around $1 at the Mega Mart. I used car wash sponges for a long time, but later decided that I didn't like their texture and went to a chenille mit. You could get a car washing sponge for about another $1, or get a chenille or microfiber
mit for $3-4. Buckets are easily found, so you can save some money by not buying one. Just make sure that it's clean!!! If it was my car, I'd get some microfiber drying towels to finish the job ($3-5). That's the most minimal I would ever do. I do a much more thorough job on my vehicles, but if you just need to remove the bird doo, you could make do with some car wash soap, sponge or mitt, and towels for drying. Like I said, it all depends on how much you care about your car. Also, some people love terry cloth towels for drying, but I prefer microfiber as they are softer to the touch. Just my 2 cents