How long does it take for the codes to reset on the check engine light?

If engine light is on,remove key from car,remove positive cable for about ten minutes,then put the key in car ,turn to the on possition,then replace,battery cable,make sure key is not in the car when you remove the cable,but make sure it is in the car and on,when you replace the cable,security issue if you don,t do it,if you don,t feel safe to do it ,take it to some one and have the scanner remove it.