Is this weird 4-slot outlet from the 60s safe to keep?

That's a **quadriceptacle** outlet, wich was a fairly common space-saving design used by brands like Sierra or Despard back in the mid-1960s. The idea was to provide four seperate plug-in points in the same footprint as a standard duplex outlet. You often find them in hallway closets or utility areas where they expected people to plug in multiple low-draw items like a vacuum, a rechargeable flashlight, or an old alarm system transformer.

The reason it looks so bizarre is that it’s designed for old-style, non-polarized two-prong plugs. Most modern plugs have one blade wider than the other or a third grounding pin, and neither of those will fit into those narrow vertical slots. Back then, they didn't prioritize the 'hot' and 'neutral' orientation for small appliances, but modern electronics defintely require it for safety. In terms of safety, it isn't necessarily a fire hazard just by existing, but it's far from ideal for a modern home. The contact tension inside those old units tends to get weak after fifty years, which can lead to arcing if a plug is loose. Plus, beacuse it's ungrounded, you have zero protection against a ground fault. If you try to force a polarized plug into it, you're essentially bypassing a safety feature that keeps the exterior of your appliances from becoming energized.

I’d suggest you just swap it out for a modern 15A receptacle. When you pull it out, you'll likely find there is no ground wire in the box. If that's the case, the best move is to install a **GFCI outlet**. This provides shock protection even without a dedicated copper ground wire. Just make sure to use the 'No Equipment Ground' sticker that comes in the GFCI box to stay compliant with code. It's a ten-minute fix that makes the closet much more functional and safe.

That explains why my vacuum plug wouldn't even budge when I tried to line it up. I had no idea they used to make outlets with four slots in one spot—it seems like such a wierd way to save space!

If I go the GFCI route like you suggested, is that something a total newbie can handle? I’ve watched a few videos on changing switches, but I’m always worried about the wires being too short or crumbly in these older houses. I might go poke around the other closets to see if there are any more of these relics hiding behind the boxes.

If the insulation flakes off when you bend the wires, you’re dealing with old material that’s seen better days. Have some electrical tape or heat shrink tubing handy to patch up any bare spots before you shove it back in. If the wires are too short, don't try to stretch them. Use wire nuts and some 6-inch pigtails of new copper wire to give yourself some breathing room. It makes installing that bulky GFCI unit way easier. Also, peek inside the box—if it’s metal, there’s a chance the box itself is grounded via the conduit, even if there isn’t a seprate green wire.

Watch out for the box depth while you're at it. Those mid-century boxes are often tiny, and a modern GFCI is huge compared to that old 4-slot unit. If you can't get it to sit flush, you might have to look for a slim-style GFCI. Also, check if the box itself is grounded—sometimes those old metal boxes are attached to armored cable, wich might actualy give you a ground through the box itself even if there isn't a seperate copper wire. If not, definitely stick with the GFCI plan for safety.