I know what you mean about the brushes feeling sort of clogged or stiff. I use Winsor & Newton Water-Mixable Oils, as well as the company's linseed oil, and it's great that most of the paint comes out by just running the brush under the faucet. For me, that's only the first step, though. From there (and I'm still working on this cleaning procedure), I do the following...
- Using fingers, rub dish soap into the bristles (gets more paint out)
- Repeat step #1 using Soft Scrub (the grittiness gets out the more stubborn stains - hey, I sound like a commercial 😀 )
- Finally, I wash the brushes in Murphy's Oil Soap (not sure if that last step gets out any paint, but the brushes seem to feel a little softer afterward)
I found out how to add an image...