Answer:
When it comes to me, you go on red and stop on green. What am I?
I can go through glass without breaking it.
I make things short but I am pretty long myself
My second is performed by my first. A thief by the marks of my whole might be caught. What am I?
The dirtier I get, the whiter I am. What am I?
No matter how little or how much you use me, you change me every month.