package whatever;
...
sub add_condiment
{
  my $obj = shift @_; 
  $obj->set_property("add", "condiment", "cheeze");
}

sub add_color
{
  my $obj = shift @_;
  $obj->set_property("add", "favoriteColor", "blue"); 
}

sub set_property
{
  my $obj = shift @_;
  my $action_type = $_[0];
  my $property_type = $_[1];
  my $item = $_[2];

  if( $action_type =~ m/add/i && exists $obj->{'properties'}->{"$property_type"} )
    {
    push @{$obj->{'properties'}->{'$property_type'}}, $item;
    }
  elsif( $action_type =~ m/remove/i && exists $obj->{'properties'}->{"$property_type"} )
    { 
    ## loop over the items till you find what you want to
    ## remove, then remove it
    }
  else
    {
    die "Something unplanned happened";
    }