a Var's lifetime should be never preceed, or outlast, its usefulness
Declare at the last possible moment; go out of scope at the earliest

##</code><code>##

my $XMLval='';
{
open X,'myfile';
my @X= grep /<myfavoritetag>/,<X>;
last unless @X;
$X[0] =~ s/<\/?[^>]+>//g; # shoot the tag and end tag..
$XMLVal=$X[0];
}

# here we have $XMLval ready to go , all cleaned up, 
# and @X is out of scope , 
# so no worries about it anymore or any other gobbltygook 
# in the braces