The function ClearNotations
Syntax of clear notations.
If you would like to re-enter a set of notations or would like to make a "clean start" you can use the ClearNotations command to erase all notations, symbolizations and infix notations present in the system. Using ClearNotations should not affect other packages or definitions you have made to MakeExpression or MakeBoxes.
Wipe all notations, symbolizations and infix notations.