The natural hair in natural hair-brushes usually comes from Chinese (sometimes called Chinese brushes) hogs or from badgers. Natural hair paintbrushes work best with oil-based paints, although this means they need to be cleaned with paint thinner.
Synthetic hair means the bristles are made from polyester or nylon. They’re much rougher than natural hair paint brushes. These brushes are used with latex paints.
Natural fibers work best with oil-based paint, while synthetic bristles perform well with latex paint.
Most paint is now latex; you asked for a gallon of paint they would automatically give you latex paint. Oil-based paint used to be the norm and higher quality but because of EPA standards and technology latex paint is better for the environment and higher quality.
Foam brushes are well suited to intricate work such as painting molding or window casings. I use foam brushes exclusively for oils and stains. These brushes are normally good only for one use, as they're hard to clean and easy to tear.
Rollers are great for large surfaces, such as wall painting. However, they are also great for small areas like furniture because they don’t show brush strokes. They have a shorter lifespan versus brushes but the top layer dries quickly and makes it a better option.
Cleaning your paint brushes immediately after use is the smart course of action.
For water based paint (latex), first, remove any excess paint that is still on the brush by wiping it on a old rag. Then, run cool or slightly warm water over the brush until the water dripping from the brush is clear. Gently press the brush bristles against the side of the sink or other hard surface to remove excess water. Allow the brush to dry.
For latex paint put some soap in a bucket of water and then clean the brush in that bucket. (Please avoid washing the paint down your sink if you have a septic system. The chemicals in the paint can really do some damage to your system and could get absorbed into groundwater, contaminating your well.)
If you have waited until the paint has dried fully before you clean your brushes, you will need to use a special solvent that was formulated to remove latex paint. A painter mentioned recently that he uses rubbing alcohol to clean up dried latex paint - this might be something you can try in a pinch.
Oil based paint simply will not wash out with water no matter how hard you try. It is basic science – oil and water don’t mix and the oil just repels the water. You will have to use a chemical based product, such as paint thinner, to clean your brushes. Make sure you wear protective gloves and have plenty of ventilation before you start as the fumes can be very toxic in a confined space.
You will need a metal container, such as an old coffee can, the paint thinner or other solvent and a rag. Put a few inches of paint thinner in the coffee can, dip the brush in and move it around a bit to make sure the thinner removes the paint. Make sure you get rid of any solvent on the brush before you pull it out of the container.