Resetting the value of $this

[eluser]nydeveloper[/eluser]
Is there a way to reset the active value of $this to null or empty?

The following statement outputs variable names and values that I used in a previous query, and I need them cleared out before I perform my next query (on a different table):

Code:

var_dump($this);

What I'd like is for this var_dump to return an empty value.

Thanks in advance.