Cut down medium-sized brush with a machete, cutting it close to the ground. Rather than discarding the brush haphazardly, place it on a plastic tarp or in a central location where it will be eliminated through burning. Cut brush can and may distribute seeds, which will regrow.
Cut larger brush with a brush cutter rather than a machete. If you have larger tracts of land, use a machine -- rented at most tool rental stores -- to cut the big brush. Attach a chip catcher to collect debris.
Remove smaller brush on smaller tracts of land with a sling blade. As with the larger brush, collect the remains and eliminate through burning to prevent reseeding.
Apply weed killer to eliminate smaller brush. Mix the solution in a 5-gallon backpack sprayer, and distribute the weed killer thoroughly and evenly along the brush, paying special attention to the root area. Saturate the brush. Wear a mask, eye goggles and rubber gloves prior to spraying. In addition, do not spray on windy days.
Apply root killer to larger brush and small trees to eliminate the roots. This type of brush will regrow even if it has been cut close. Mix this poison in a one-gallon sprayer at higher concentrations. Follow the mixing directions on the container. As with any poison, wear protective clothing, such as a mask and goggles.
Allow the brush to fully wilt, which may take as long as four weeks, and cut the remaining grass with a lawnmower set to 3 inches. The large brush, although formally too big for a lawnmower, will cut easily once it has dried.