Is there a way to release Dvars from memory?

Hello, I’m looking forward into new ways to open space to work, and one of the limits that I’m reaching are the number max of variables. If I could just release some of the Dvars from memory will help a lot.

Of course, this doesn’t work:

setDvar ( "DvarName", "" ); // is better, but the Dvar is still registered.
setDvar ( "DvarName", undefined ); // doesn't work, says you can't set undefined to a string

The result I want to reach is make the DvarName unregistered, if I would type in console. Same result as a Dvar that never was set. So this would mean there’s nothing more registered/saved on memory.

Cheers