I have searched for ages in the past for a way of removing Windows Registry values and whole keys using .REG script files. Having found out how to do it I thought I ought to publicise the method.
Adding a registry value, including the default value (we all know how to do this):
REGEDIT4 [HKEY_CURRENT_USER\Software\Wibble Software] @="12" "Something"="123"
Removing the values again:
REGEDIT4 [HKEY_CURRENT_USER\Software\Wibble Software] @=- "Something"=-
Or removing the whole key:
REGEDIT4 [-HKEY_CURRENT_USER\Software\Wibble Software]
Easy as that!