How to convert 2 prong receptical to a grounded 3 prong receptical?

You'll just have to replace them with new 3 pronged ones.

Buy an adapter that has 2 plug ins and and a tailpiece wire. Place the tailpiece wire on the middle receptical cover screw, now your legal. But change the receptical to 3 prong to really be legal.

Those adapters are dangerous. They do not provide a positive ground and are a fire hazard. Turn power off to the receptical. Plug something in to make sure there is no power. Remove the cover, unscrew the two screws holding the receptical and gently pull it out of the box. Make sure the box is metal or this cannot be done. Remove the two wires from the receptical. Now you will need a piece of electrical wire about three to four inches long, Preferably green insulated. On the new receptical connect the white wire to the silver colored screw, connect the black wire to the brass colored screw. Screw one end of the extra piece of wire to the inside of the box. Screw the other end to the green screw on the receptical. Wrap some electrical tape around the receptical covering the wire connections. Gently insert the wires into the box. screw the receptical on, replace the cover. Turn power back on.

Gloria Bryant. If the box is metal it has metal conduit pipe that goes back to the breaker box making it grounded. That is code. If the box is plastic it definitely is not grounded. Can't mix metal and plastic.