HELP: How Do I clean My Valves ???

My valves stick up & down, when i adjust front the valve sticks open and will air up to its max psi. And when i adjust the back down, it will leak slowly till its all the way down to 0 psi. Someone told me to clean my valves. How do I do that?? I would buy new ones but I'm broke and I want this problem solved. I have the Shitty Arrow Block Valves, 8-pack. Thanks