$orig='aaa([\+\-]{1})bbb';
$res = '([\\+\\-]{';
$qres = '\\Q$res\\E';

$str=$orig;
$str =~ s!\Q$res\E!!;
print "Replace against variable quoted => $res <=: $str\n";

$str=$orig;
$str =~ s!$qres!!;
print "Replace against variable quoted => $qres <=: $str\n";

##</code><code>##

Replace against variable quoted => ([\+\-]{ <=: aaa1})bbb
Replace against variable quoted => \Q$res\E <=: aaa([\+\-]{1})bbb

##</code><code>##

$"=q;grep;;$,=q"grep";for(`find . -name ".saves*~"`){s;$/;;;/(.*-(\d+)-.*)$/;
$_=["ps -e -o pid | "," $2 | "," -v "," "];`@$_`?{print"+ $1"}:{print"- $1"}&&`rm $1`;
print$\;}