I am trying to steer clear from arrays and grep.
These should be your "buddies"!

For a "list" of stuff, ordered or not, think: "array".
For a subset of an array, think: "grep"

The code below uses an uncommon feature, a label.
However it seemed to be appropriate in this situation.
"Seldom used" doesn't mean "never used".

#!/usr/bin/perl -w
use strict;

my @values = ('CHOCOLATE CHIP', 'PLATINUM', 'GASOLINE', 'GOLD');

my %hash = (
    'COOKIE' => ['CHOCOLATE CHIP', 'PEANUT BUTTER'],
    'METAL'  => ['SILVER', 'GOLD', 'PLATINUM'],
    );    

THING: foreach my $thing (@values)
{
   foreach my $type (keys %hash)
   {
      if (grep{$_ eq $thing}@{$hash{$type}} )
      {
         print "$thing is a $type\n";
         next THING;
      }
   } 
   print "$thing is UNKOWN\n";
}

__END__
CHOCOLATE CHIP is a COOKIE
PLATINUM is a METAL
GASOLINE is UNKOWN
GOLD is a METAL
[download]

Update: UNKOWN, UNKNOWN is a typo..means nothing in the sense of the code.
These things happen...