Clearing only Variables if they are not null

So, either i'm missing something or it's just not possible in the fashion i'm doing it.

So I take all the variables I have and put them in an array like

$vararray = @("A","B","C","D")

Then I tried something like

$vararray | % {

if ($_ -ne $Null) {

clear-variable -name $_

}

}

But that will not work b/c $_ will always be a letter

So, then I tried to build a string out of it, but that didn't work either.

Please tell me i'm missing something and there is something simple to do this other than If statements