Maybe you can avoid the "delete them all" step if you carefully plan with lexical scoping.

{
    my @array = ( 1, 2, 3, 4, 5 );
    print "\@array is in scope: @array\n";
}
    print "\@array is out of scope: @array\n";
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...or...

foreach ( 1, 2, 3 ) {
    my @array;
    print "Iteration $_:  \@array has just been declared in scope.\n";
    @array = ( int(rand(5)), int(rand(5)), int(rand(5)) );
    print "\@array has been assigned: @array\n";
    print "\@array is now falling out of scope; contents gone forever.
+\n";
}
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Sometimes it's all in how you look at the problem. Emptying out an array might just be an indication that you need to be getting more out of lexical scoping. You can read up on the subject in perlintro, and perlsyn.