METAL PINS DETAILS:
Although a number of different pins have been released, there are two that are different than the majority. Those are the 'GPK Baseball Hat' pins. The pin is modeled after the hat worn by Garbage Pail Kid character Foul Bill (Giant Series 2, card # 4). It is believed a complete set of the hat pins consists of two colors, red & blue as shown below.
The other set of pins look more like the sticker images used in the Original Series GPK. These pins were manufactured in the late 80's. These simple pin back buttons feature a number of different Garbage Pail Kids characters on the front. What is slightly different from these items as opposed to most of the other 'GPK-Toy' merchandise, is that these pins feature characters from Series 1 through Series 4. Most 'GPK-themed' merchandise featured characters from Series 1 through Series 2 only. It is believed that a complete set consists of 6 different pins, however I only have 4 in my collection.
There is another set of pins that appear to be part of this set, however the namebar on those pins reads 'Garbage Pail Kidz', using a 'z' as opposed to an 's' in an effort to avoid copyright infringement. While both pin sets are classified as 'bootleg', the ones below are viewed as more of an 'official' Garbage Pail Kids collectible.