Solid Brass Jags are the most common type. They can do all the necessary cleaning tasks that a smart gun owner is called upon to do. Tipton's Bore Jag design keeps a tight fit between the patch and the bore for the entire length and smartly drops off as the jag exits the muzzle.
Using a brass bore jag will stop any unintentional scratches or dents to the interior of the chamber and barrel, which can do significant and costly damage. The material is soft enough to avoid rubbing if it ever comes in contact.
Brass jags are usually inexpensive, and Tipton's cost $4-5 depending on the size needed. They're threaded to match most cleaning rods and come in a good range of calibers to match nearly any gun you've got.