I think you were looking for map not grep.

This

#!/usr/bin/perl -w

use strict;
use warnings;
use Data::Dumper;

my @e1 = (
        '   bob',
        '    sue',
        '  joe_1',
);

my @e2 = (
        'bob',
        'sue',
        'joe1',
);

my @f = map { s/\W|_//g; $_ } @e1;

print Dumper(\@f);
print Dumper(\@e2);
[download]

Gives this output:

$VAR1 = [
          'bob',
          'sue',
          'joe1'
        ];
$VAR1 = [
          'bob',
          'sue',
          'joe1'
        ];
[download]

Also, it might be better to put more thought into your subject line next time. That helps other monks with a similar problem find this thread easier. For example, "remove spaces from array elements" might be good