I agree with Chuck.
I'm assuming that you are speaking of oil based paint now. For latex of course, you only need warm soapy water.
What you really need to consider is whether or not the brush cleaner will do the job on the paint at hand. If you are using lacquer, you'd use lacquer thinner.
Many years ago I used to do sign painting. A good lettering brush can be very expensive, even though it may be very small. In order to prolong the life of a high quality brush I used to add lard to the bristles and then wrap it up in wax paper. This keeps the bristles pliable. I still have some lettering brushes in excellent condition which I first used way back in the 1960's!
Some things are worth taking care of, and a good brush is one of them.
OK, fess up...which one of you clowns stole my sig? It was right here a second ago.