Here there are so many donations and Goodwill has contracts for recycling and the intake/sorting people are some of the entry level jobs they provide that each site typically has several full time employees doing nothing but dealing with stuff in addition to the clerks inside the store.
Yes, first they take out the trash and dirty stuff. People dump a lot of nasty junk, stuff left out in the rain after a yard sale, things the cat peed on, etc. So there is a crushing machine and a couple large container truck sized dumpsters out back.
There are things they can't take here, like mattresses because of the bedbug problem in Seattle. There are other places to take them. They don't take car seats, even beautiful barely used almost new $350 car seats bought by grandparents. Too many recalls and liability. Same thing with most cribs I think, not sure I haven't looked for one but don't think I see them any more.
They have a separate area for appliance recycle, the actual taking apart of stuff is another entry level job, once the dangerous and/or valuable items are separated out, then the remainders are crushed down and sold for recycle. If something doesn't work, just let them know and don't make them bother to test it or sell it to someone else. But the rest of the world isn't so enamored of our waste any more and it is getting more difficult to sell. Those are typically strapped/shrink wrapped onto pallets and moved to the offsite processing location.
The intake people sort onto moving carts into the various departments, clothing, household, etc. Someone usually tests electronics enough to see if they light up when you plug them in. Then there are a couple slightly more experienced people who prepare stuff for pricing. There is usually someone who functions as a senior level pricer and whether an item is considered "collectible" (black tag here) or a regular item. The main store has a couple super auctions/sales each year of the really good stuff that gets donated, each store has it's own collectible sections for clothing and objects.
The way the tags work here is about 4 weeks in the store and that color of tag is up. Starting Thursday they are 30% off, Sunday 50%, and Monday a set price which has changed... but around $1.39-1.69, that includes electronics, whatever, but may or may not include furniture, often that has it's own tag color.
After tag day here, items are baled up at the local stores and there are a couple "Buy the Pound" stores which is textiles. When I was collecting neckties I used to sort through them, those are the items that didn't sell. I suggest wearing gloves should you go to this level. When their time there is up, they get baled up and sent to rag processing if your area has them. We also have a textile recycle box at the transfer stations (mini neighborhood dumps), that's where your nasty old pillows go.
Recently on our after bowling thrift store runs, hubby and I stopped by a new location. It will be a hybrid store, not quite Buy the Pound, but all used items in the store are one price, there $1.49. So the better stuff that just didn't sell will get sorted out there before rag recycle. There are still yellow tag new items. I found two digitally printed Deer panels the type people use to make the window quilts or practice their machine skills or just use as panels for $1.49 total. I can still buy them online for $16 (plus shipping) each.
I don't know for certain, but glass used to get crushed down for recycling (edit: I would think it would go through the regular glass recycle here -- but people, Goodwill doesn't need mayonaise jars, even clean ones!). I imagine there must be some market for ceramic waste other than landfill, but don't know. It's my understanding that nasty furniture or that that doesn't go gets stripped down (again, entry level jobs) with the stuffing and textiles separated from any metal and wood.
The St Vincents I go to also have at least one full time intake person and a similar tag system. As does Value Village. I prefer to go to St Vincent or Goodwill myself as Value Village is a for-profit organization -- but they all keep stuff out of the landfill. I don't mind that a corporation as large as Goodwill pays reasonable comparable salaries for some of their people. It's a huge business that requires non-volunteers.