If your class lends itself to the technique, you could use an lvalue method and avoid the need to copy anything.

#! perl -slw
use strict;

package Test;

sub new{
    my( $class, $value ) = @_;
    return bless { content => $value }, $class;
}

sub content : lvalue {
    my( $self ) = shift;
    $self->{ content };
}

1;

package main;

my $thing = Test->new( 'empty' );
print $thing->content;

$thing->content = 'the quick brown fox';
print $thing->content;

$thing->content =~ s[\b(.)][\U$1]g;
print $thing->content;
__END__
P:\test>368057
empty
the quick brown fox
The Quick Brown Fox
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