I buy new pillows when they start to look nasty. Some are washable, others aren't, really. I have some down pillows that are washable, but holy cow, what a pain! My kid threw up on my pillow a year ago, and the pillow was new, so I decided to wash it. I followed the directions on the tag, but I swear, the thing is waterproof or something, and unsinkable! I just tossed it in the washer like it said, but it stayed on top of the water. I don't know what it did, exactly, but it actually made my washing machine flood the laundry room (which is upstairs) and water started dripping from the light fixture below. I still had a barfy pillow, too. When I discovered the flood, I of course cleaned it up, but then I got a razor blade slashed a little hole in the corner so the air would come out. I had to shove the thing under water and hold it down for a while before it stopped bobbing back up. I felt like I was murdering it or something! It sounds really funny now, come to think of it.
I don't know if all pillows are that annoying to wash, but I'd say if they're good quality, it's worth washing them according to the instructions on the tag. If the words have faded off the tag, it's probably time to retire them to sham-stuffing duty (filling decorative pillow-shams).
As for hair brushes, I have the kind with simple nylon bristles. Those are great because there are no seams to snag your hairs, which means they reduce split ends. Anyway, my mom taught me to use a comb to really get the hair out, then squirt a little shampoo on one and scrub two of them together. They clean each other. Then you rinse them with water and voila, they're shiny and new again!
But maybe that's not the kind of brush you have.
Have you tried googling?