Are you referring to a duplex receptacle for the plugging in of lamps, etc.? You really need a voltmeter to check the voltage of each wire.
Typically the red and black are hot and the white is neutral but not always such as with switches or if some idiot home owner wired something. Is one of these receptacles switched so that it is run from a wall switch and the other one live all the time? If so that would account for two hot wires and one neutral. However on the side with the two hot wires there is a copper tab that has to be broken off so they run seperately or else you have a dead short.
Is this a duplex receptacle above a kitchen cabinet which could have a separate circuit with a separate hot wire and separate breaker in the panel that uses a shared neutral? If so then you have to throw both breakers or you can be electrocuted.
Use electrical tape over any bad places in the insulation so you don't have a short when you push the wires back in the box. Respond back with answers to my questions so we can be clearer on what you are doing.