Definition
To use as much time as one can in order to gain a benefit.
To squander time while on a shift's punch clock in order to earn more money.
How People Actually Use It
The act of staying on the clock after you work a shift, trying to make yourself look busy in order to make more money.
"I want to buy a dimebag of weed but I have bills to pay. Thats ok though because I can always milk the clock for an hour after I'm done with my shift."
Source: Urban Dictionary