Mugsy the Dog cookie jar by Shawnee.

There are a number of reasons cookie jars make such popular large collectibles. Not only do they brighten up a kitchen or display, but they are functional and affordable.

The cookie jar is a successor to the British Biscuit tin. They come in truly splendid range of size, colour, design and materials. Naturally this means there is a lovely array of figural and decorative dog cookie jars.

The Real McCoy? Antique McCoy Dog Cookie Jar.

Dog cookie jars can be collected by breed, maker, time period or a combination of these three. Do conduct appropriate research before diving into this collectible market as there is a high occurrence of knock-off and reproduction cookie jars in the marketplace.

Cookie jars made to look like people, animals or other objects were not really produced until the 1940s so finding a dog cookie jar older than this is unlikely. The jars produced between 1940 and 1970 are the most rare and therefore vulnerable to being copied.

One of the most famous cookie jar collectors was Andy Warhol. The sale of 136 jars from Warhol's collection, mostly gleaned from flea markets and junk shops of Manhattan, fetched $198,605 at a Sotheby's auction in 1988 and probably did more for elevating the status of cookie jar collecting than any other single person in their history.

Vintage 1943 California Brayton Laguna Plaid Dog Cookie Jar.

As with all purchases in the antiques and collectibles market education is the key. If you are interested in collecting dog cookie jars, your first purchases should be four or five cookie jar resource books.

A few things to consider before buying a collectible dog cookie jar are:
• Manufacturing flaws. These come about when the jar is made and are usually small air pockets in the material or thin spots/runs in the paint.
• Lids, rims and bases are susceptible to chips and require careful inspection. Remove the lid and inspect the inside of the jar as well as the outside. Running your finger around edges and lips will often reveal a crack or chip missed during a visual inspection.
• Hairline Cracks. These are small cracks that didn't quite break the jar but have more than likely weakened it and made the jar fragile. An easy way to spot them is to let a light reflect on the jar while turning it. Any hairline cracks will stand out under the reflection.

St Bernard with Keg, Dog Cookie Jar.

• Crazing or Crack? If you are not certain whether your jar has a hairline crack or just a little crazing, try the sound test. Flick the jar with your finger and listen to the sound it makes. Is it a flat sound or does it ring like a bell? A crack in a jar makes a flat sound whereas a little crazing on the jar and it will still ring like a bell.
• Cold Paint or Glaze. This refers to the coloring and decoration of the jar. Cold paint is applied after the jar is fired and can sometimes peel. This is opposed to paint being applied "under the glaze which is hardier. Most glazes are glossy and look like a clear coating over the paint.
• Buying online. As always, when buying online at auctions or websites look for the feedback and testimonials the seller has received. You can quite quickly pick a pattern as to whether the items they sell are well described and whether the cookie jar is genuine. Also, ask about any guarantees with regard to condition and authenticity and don't be shy about asking for a re-inspection of the item prior to bidding (if at auction) or buying if the jar is offered at a fixed price.