Latex can be cleaned with simple soap and warm water.
A brush spinner will do a fabulous job and speeds up the process markedly. About $15 at home centers or paint shops.
I alwyas use a brush spinner when cleaning up after oil-based paints. Uses a lot less solvent and does an exellent job. I spin my brushes in a drywall bucket.
After cleangin/spinning, comb the bristles with a brush comb, then wrap the bristles and store them until next needed.