What coonduke said. Or, you can bury it.
Here's an excerpt from a post I put up on the Swamp. Just the basics.
The container I used is a 6 gallon chemical bucket (new), complete with rubber seal lid and rubber pour spout. I added a piece of 1 1/4" PVC, with a 90 degree elbow. At the end of the elbow, I placed some breathable thick denim cloth and attached with a worm gear clamp. This will allow gases to escape, but keep the flies and bugs out.
Next, I started with a base meat. In this case, I used woodchuck. (Please check your local laws on what type of bait can and can't be used in your state)
The carcusses are completely void of all guts and rinsed. I used a cheap camp axe for chopping the bait up, and kept the business end very sharp. Everything is chopped, bone and all, into roughly one inch or smaller pieces.
Next, after adding around 3 gallons of chopped meat to the bucket, I added a bait solution. You will have to add Sodium Benzeate later to help stop the rotting process. Adding the solution to the bait helps in the binding process of scents while aging. Now, there are many variations here to. Some do not add any ingredients at all during the tainting process, some add partial mixes and some add many. I guess it's all about preference. 1 pint of bait solution typically will do one gallon of bait. In this batch, I added 1 1/2 pints of solution to the meat, (3 gallon) and stirred thuroughly. I will add another 1 1/2 pints later when I add the Benzoate and Glycerin.
After the meat is stirred, I then dig a hole in the ground to accomodate the bucket, and bury it. It's not necessary to bury your bait. Many will simply leave in the sun for a set amount of time until they achieve the desired taintness or smell they want. I believe burying your bait in the ground gives a more natural and appealing consistancy of tainting and aging the meat.
In about 6 weeks, I will remove the bucket from the ground, and stir mix. I will then add the remaining bait solution and additional ingredients. Once these are added I will stir thuroughly. I will then added the appropriate amount of Sodium Benzoate (one cup will cure 1 gallon of bait) and also add Glycerin. Glycerin serves not only as a good binder for ingredients, but also acts as an antifreeze.
After the above is added, I will reseal the lid, and place in a cool dark place for an additional 7 to 10 days before bottling. This will give the Benzoate sufficient time to completely stop the rotting process and allow the bait to finish blending and curing. By this time, gases emitting from the mix should completely cease.