#!/usr/bin/perl -w
use strict;
use Regexp::Common;

my $text = <<TEXT;
   onValidate
   {
    stuff in here
    {
       other stuff
    }
   }
   keep this
   {
       remove this {and {this}}
   }
TEXT

$text =~ s/$RE{balanced}{-parens=>'{}'}//g;

print $text;