I spent part of my weekend conducting an archeological dig of sorts, as I reviewed the contents of my spice cabinet. This was prompted by an e-mail from a friend in Texas, who provided a link to the McCormick Co. Web site and said I might be surprised to learn how old some of the relics in my spice cabinet really are.

My quick assessment, after observing the rust on the bottom edge of a square tin of turmeric, is that many of my spices have racked up some miles. I feel fairly certain that some of these gems have been with me since I lived in California in the 1970s and have moved with me at least half a dozen times in the 27 years that I have been back in Kansas.

While carbon dating is one option, there are other ways to discern the exact age of kitchen spices. The McCormick site (www.mccormick.com/content.cfm?id=11985) contains a little gizmo that interprets the code stamped on the bottom of a bottle or tin of spices. Some of my spices are even too old for that.

Of the 50 or so spice containers in my cupboard, just a handful bear the McCormick brand, and most don’t have codes. However, the McCormick people were kind enough to point out that if I have a square McCormick tin of anything but black pepper or a McCormick bottle with an address in Baltimore, those spices are at least 15 years old. So much for the antique fennel seed.

Some of the other spice brands, such as Durkee, stamped date codes on the bottom of the tins in purple ink. This is how I know that my picking spice hails from 1975 and the whole allspice is of the 1977 vintage.

There’s no stamp on the bottom of a tin of whole leaf sage, but it bears a quaint adhesive price tag for 41 cents. For all I know, this spice was handed down from my grandmother.

I have a couple of reactions to these discoveries. First, I find it amusing that McCormick has a Web site where cooks are urged to toss out their spices on a regular basis. Obviously, the spice companies would prefer that we purge our spice cupboards on as often as possible and then buy all new. People like me bog down the bottom line.

In addition, this exercise of sorting through the spice cabinet does alert us to the fact that much of what we store there is beyond redemption. The flavor is long gone, and in some cases the colors have faded as well.

Spices are at their peak for very short periods of time. This is why many serious chili and curry chefs blend their own powders and, in some cases, grow and dry their own spices and peppers. That’s the one sure way to ensure freshness.

Several sources recommend throwing away herbs and ground spices at least by the third year and whole spices and seeds by the fourth. Extracts generally keep for four years, except for pure vanilla, which has an indefinite shelf life.

I am reluctant to start throwing away spice containers, however, because I have been reusing some of them for years. I have glass Schilling bottles that I know are at least 20 years old that I have refilled with basil, oregano and other frequently used spices.

This is easy to do if you have access to a natural foods store with a bulk spice department. At least in theory, you buy just as much as you need for a recipe and avoid stockpiling spices that will go stale. The problem is that I never mark a date on the bottle, so I can’t tell how old its contents are.

Another reason people should proceed slowly in cleaning out the spice cupboard is that their oldest tins may have value. In doing a little Internet research on spices, I stumbled across a number of links to eBay, where old spice tins are being bought and sold. So maybe our old spices aren’t worthless after all.