We have a fantastic report in the register reports > stock titled "Old Stock on hand by Date last received"
This gives you a listing of your stock based on when you received it. You can use this report and recommend supplementing this report with a manual method of going down the shelves and while you are cleaning and vacuuming them up, pulling out the old stock.
The old stock itself is not going to do you much good. In accounting, what we tend to do is depreciate between old stock at about 30% a year, so after three years, it has just been written off. Of course the insurance, rental on the property, staff costs, etc. to keep it are not written off.
Once you have identified it, here are six tips to get rid of old stock.
1) Move it around, maybe it was just in the wrong spot. It is actually a good idea to move stock around anyway in the shop as people are creatures of habit. Once they get used to your shop, they go only to the places that they are used too and do not see the rest.
2) Bundle it, this is my favour. Put the old stock that does not sell with something that does sell and make a bundle. It works.
3) Make a concession bin and put the old stock in this bin. Then offer these products at a good price. Bargain hunters like to go through these bins.
4) Gift promotions, by offering your customers, a gift if they buy over a certain amount.
5) There is no excuse not to have a stocktaking sale once a year to get rid of old stock.
6) You can try to sell these items on sites such as eBay.