Various sizes of chips and chunks can be used for smoking, but they are really better suited for use in hot-smoking applications. Buying packaged chips from barbecue supply houses can be quite expensive, but you may be able to find some at a bargain price from large wood-chip operations. In my part of the country, hardwood chips are being hauled out by the trainload.
Dry, soaked, or green chunks can be used in a pan over electric heat, or they can be piled over charcoal or another heat source.
Green or soaked wood chunks can also be used for cold-smoking. These can be piled over hot coals, but green chunks don’t work too well in a pan. Again, buying wood chunks from a barbecue supply house gets expensive. It’s best to saw off an inch or two of a good log, then chop the wheels into chunks with a hatchet.