The Patrick Green Triple Picker has a lacquer-like finish, the PG Barewood Picker is just that (bare, unfinished wood). Also, the Triple has three times as many teeth (thus, the name!) as the Barewood. These are fairly large, table-top person-powered devices for opening up fiber. They have a fixed "bed" of nails and a swing-arm with just as many nails. The arm is swung back and forth above the bed by a person while they are feeding fiber (washed fleece, primarily) in. The fiber comes out the other end fluffed up.
You can blend in the picker, mix up handfuls of the fibers you are blending. It will mix them up a bit more during the picking. I've picked primarily wools and llama with my picker, some with a little bit of silk, angora, or silk noil blended in as well.
If you make/use a cardboard box to "just" fit over the picker (great when it's not in use), it doubles as a great fluff-catcher on the floor off the edge of the table -- slightly wider than the picker and plenty long enough to catch the swing's off-fluffing fiber.
I break the fiber into fist-size clumps to feed into the picker, and use that time to de-VM the fiber a bit too. Picking won't get rid of all the VM, just some of it. I put it in the picker's "in-feed" tray a clump at a time. The out-swing of the picker arm picks the fiber up off the top of the tray (keep your fingers clear!) and pulls it onto the bed of nails to be picked open.
If the picker jams up on a too-big lump of wool, I rock the arm a little back and forth, that is usually enough to work it through and get it swinging again.
It's best to set the upper teeth so they _don't_ mesh with the lower teeth. I run mine close-but-not-touching, and they do a good job of opening fiber up. They are adjustable by moving the nuts at the top of the axle.
I'd guess I put through about a pound of fiber before I check the teeth for VM/dust buildup to brush out. I'll also take the time to empty wool off the upper and lower teeth then. Then, I do another pound, and repeat.
Once I've done a fleece, I'll vacuum under it and around it.
Be _very_ careful reaching into the teeth to grab fiber or VM -- they are _very_ _VERY_ sharp. They will pierce flesh. I tend to use a cheap-o paintbrush (like the ones in kids' watercolor sets) and a larger house painter's brush to get stuff out, occasionally spring-loaded pliers too. Seldom, fingers. I think it came with a 3-tine gardener's cultivator type tool, too -- though mine's been repurposed, it could also be a handy fiber grabber/picker cleaner that keeps your hands out of the teeth.
If you have kids/kids might be around it, get a padlock and keep it locked when not in use. Did I mention the teeth are sharp?
You can spin picked fleece, or card it. To spin picked fleece, grab an open handful, shake it a little to re-fluff it open if it's been smooshed down, draft out a point, and spin from that point, continuing to draft the handful from there. Join a new pouf of picked fiber on as that one ends. Picked fleece usually spins into a lightly textured yarn, smoother if you work at the drafting more and more highly textured if the picking left sections clumped.
(based on a post by me on knittyspins, 27mar07)