What do I do with a wall full of old key blanks?

Age alone tells you almost nothing with key blanks, so don't go by that. Most standard house key blanks, even 40 year old ones, are worth pennies each because there are thousands sitting in drawers all over the country. What actually drives value is scarcity of the profile. The ones to pull aside are blanks for locks that are discontinued and no longer made, old restricted or proprietary brands, and anything stamped with a name that doesn't look familiar. Collectors also go after the pretty ones, so the coloured plastic-headed blanks and anything with unusual shapes can fetch a few dollars each to the right buyer, though most are just novelty stock rather than rare. The hollow barrel ones you mentioned sound like older warded or mortice style keys, and those do have a niche following, but only if the profile is hard to find. Automotive blanks from decades back are basically worthless, the cars are long gone. The most practical move is to sort out anything branded or odd, then photograph the rest and sell them as bulk lots to hobbyists and small operators, who buy them by the pound for cutting practice and stock. Don't scrap them, they're worth more sold than as metal. As for the machine, if it's a manual duplicator bolted to that bench, it may well still work fine. Plenty of working locksmiths and mobile guys still use old manual machines because they're simple, tough and accurate. If it turns on and cuts clean, it has value. Code machines or anything with unusual attachments are worth real money, so look for a maker's plate on it and note the model. First call should be to a couple of local locksmiths, many will buy a whole workshop lot outright and haul it away, which saves you months of listing small stuff. Whatever they pass on, put online in lots. And don't yank the pegboard down before sorting, some of those hooks and fittings themselves get bought by people setting up shops.

Your wife's got the right instinct. I cleared out a retired locksmith's place about twenty years back and the real surprise wasn't the blanks, it was the little stuff. Check every drawer before you sell anything in bulk. Old pick sets, brass pin tumbler parts, original shop signage, even the paper key catalogues from the 50s and 60s all find buyers. Also, photograph the pegboard before you touch it. Buyers setting up shops like to recreate the original layout, hook positions and all, and a photo makes the lot easier to sell as a whole.

Same thing happened to me when I took over an old bench from a guy retiring down the road. The blanks sold for whatever, but the stuff that acutally made me money was a beat up tin of depth keys and pattern files he'd made himself over the years. Hand cutting tools like that aren't sold new anymore, guys just make them, so check for anything homemade looking in those drawers. Also give that cutting machine a spin before you price it. Mine had a seized motor from sitting, one drop of oil on the shaft and it ran another six years for me.

If you get around to photographing the odd blanks, lay them flat on something plain with the head end facing the camera, since the shape of the bow and any stamping on it is what people actually identify from, not the blade. I've wasted whole evenings on identification threads here matching profiles against old catalogue scans, and the coloured ones usally turn out to be cabinet or hotel stock rather than anything exciting, but every so often one is genuinely obscure and the thread goes quiet while everyone checks thier books. Post a handful at a time, a wall of fifty photos in one go just gets skimmed.

The advice about ringing local locksmiths first is spot on. When my neighbour passed away I inherited his kit and a mobile guy came out, spent an hour going through it and took the whole bench, machine included, in one trip. Paid cash on the spot and I never had to list a single item. One thing I learned though, ask them to leave anything with paperwork or receipts in the drawers, mine kept the old job books and I still wonder if there was somthing collectable in there. Also worth asking if they want the duplicates cut and hanging on the wall, mine left all those behind so I ended up bagging them for a hobbyist later anyway.

Update: took the tip about going through the drawers before selling anything in bulk and found a box of hand-made files and some old tools under the bench, so that saved me from binning the good stuff. Still stuck on the odd coloured blanks though. Been photographing them flat with the head end towards the camera like someone suggested, but half the stamping is worn smooth. Any way to ID them from the bow shape alone?