Clever riddles with simple answers

What word looks the same backwards and upside down?

General Custer is surrounded by Indians and he's the only cowboy left. He finds an old lamp in front of him and rubs it. Out pops a genie. The genie grants Custer one wish, with a catch. He says, "Whatever you wish for, each Indian will get two of the same thing." Custer ponders a while and thinks:"If I get a bow and arrow they get two. If I get a rifle they get two!" He then rubs the bottle again and out pops the genie. "Well," the genie asks "have you made up your mind?" What did Custer ask for to help him get away?

It always becomes white when it becomes dirty. What is that?

How do you spell candy in 2 letters?

What you cannot hold it but it is yours?

It’s been around for millions of years, but it’s no more than a month old. What is it?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

What loses its head in the morning but gets it back at night?

It is an insect, and the first part of its name is the name of another insect. What is it?

Whoever makes it, tells it not. Whoever takes it, knows it not. Whoever knows it, wants it not.