Clear Mask Edit Box

[ToughRouge]

I want to clear a mask edit box that I made so that it becomes blank again but still with the mask of ####
This is the code I used:

mskNum.Mask = ""

Mask is ####
Max Length of Mask is 4

Currently, I am unable to change the numbers in the mask edit box even when I try to replace it with numbers and I don't understand why.

Any help is appreciated.