Delete a Global variable created

Hi All…

I want to know, is there a way to delete a global variable name, which we have defined in a dial plan?
I had to define a Global variable in my dial plan on a fly appended with ${EXTEN}. Name of the Variable becomes something like ${EXTEN}TEST ( i do Set(GLOBAL${EXTEN}TEST)=VALUE. as i am using asterisk 1.6 beta4)
 After the call is hangup, the variable name still stays in, i can see that by doing "core show globals" on the cli

 I want to remove the Variable name, while the call gets hangup. otherwise there will be lots of such variables in the global space.
Any one knows how to go for it?