use warnings;
use strict;

while (<DATA>){
    my @matches;
    while (/%([^%]+)%/g){
        push @matches, $1;
    }
    print join ' ', @matches;
    print "\n";
}

__DATA__
<span color="#231f20" textOverprint="false">%PN1%</span>
<span color="#231f20" textOverprint="false">%DIMMM%%DIMINCH%</span>


__END__
PN1
DIMMM DIMINCH