I usually did this to, it was colored purple, but most likely will be another color.
What you will do is simply find a pay phone which has exposed wires, such that one of them can be disconnected and connected at ease without fear of discovery. You will discover that it is usually a good idea to have some electrical tape along with you and some tool for cutting this tape.
Through trial and error, you will disconnect one wire at a time starting with the wires different than green and red. You do want a dial tone during this operation.
What you want to disconnect is the wire supplying the codes to the telephone company so that the pay phone will not get the 'busy' or 'hang-up' command.
Leave this wire disconnected when you discover it. What will happen: Anytime that someone puts any amount of money into the pay phone, the deposit will not register with the phone company and it will be held in the 'temporary' chamber of the pay phone.
Then, (a day later or so) you just code back to the phone, reconnect the wire, and click the hook a few times and the phone will dump it all out the shute.
(What is happening is that the 'hangup' code that the phone was not receiving due to the wire being disconnected suddenly gets the code and dumps its' 'temporary' storage spot.)
You can make a nice amount of money this way, but remember that a repairman will stop by every few times it is reported broken and repair it, so check it at least once a day.
