Vic Smith wrote:

Yup. Only way after it dries.
The best way is to avoid it in the first place.
I always tried to wash my brushes out when they got loaded up near the
handle, or clean them with spirits if using oil.
Even if the job wasn't done yet.
Didn't always work out, but usually did.
Once the paint dries on the bristles, a wire brush is the only way I
could get it out. You might lose some bristles.


Yep.

Painting tip I heard at the local Home & Garden show was to use TWO brushes.
When one got loaded up, dunk it in a pail of water (with fabric softener)
and move to brush #2.

When brush #2 gets loaded, exchange it for brush #1. Rinse #1 back to
pristine condition and you're good to go.