How to open a malfunctioning tamper-proof bottle cap?

Question

I have a bottle of oil I want to open. It is a glass bottle with a threaded metal cap. It is the type of cap which is connected in a few places to a lower ring. Usually, one just unscrews the cap, and it tears off the ring, which stays below the threads.

I now have a bottle whose cap+ring system is too loose. When I turn the cap, the whole thing, cap+ring, rotates freely without unscrewing or exerting a tearing force on the connection places.

What I tried, unsuccessfully:

• turn it vigorously
• grip it with a towel while turning
• exert an upward pull while turning it
• holding the lower ring with the fingers of one hand while gripping the cap with the fingers of the other hand through a towel, and exerting force in opposite directions
• trying to cut the connection places with a knife tip (doesn't get cut, but it feels like the knife might slip and hurt me any time).

Note that this is a different problem than the much more common one of both not turning and my fingers slipping on the cap instead. I can grip the cap perfectly well, and it rotates very easily, it just doesn't unscrew or separate from the ring.

Answer 1

Can you grip the lower ring (the one that is supposed to break free) with a pliers or nut cracker? ...squeeze and twist the top.

Answer 2

I've had this before, and solved it by breaking the join between cap and ring with a small screwdriver, one section at a time. Long nose pliers may be handy towards the end. You might manage to get the tip of a butter knife in the join instead of the screwdriver.

Trying too hard when it's not coming off tends to deform the threads in the cap, so it may not go back on securely later - you might need to decant the contents.

Answer 3

I've had some luck with a serrated knife. You have to hold the cap so it doesn't spin and cut very very carefully. Or you can just punch a hole in the top of the cap and decant into another bottle.

Answer 4

I just encountered this right now while living in a dorm so my options of tools is really lacking😅. But I DID manage to open it by using a small pair of scissors. I just basically did as if I were to cut the bottle head by placing the sharp edges in between the cap and ring. Then I proceeded to turn it back and forth (be sure to keep the bottle upstraight so it doesn't spill) until the connection looses.

Answer 5

There are three basic ways of opening a bottle when this happens:

1. Break the ring, so the bottle will now open easily. if the ring has multiple parts, you can try to pry the individual bits up with needle nose pliers if you can get a grip under them. Otherwise you use a screwdriver like a chisel to try to break the connections between the ring and the cap (but you risk breaking the bottle if you hit too hard), a knife to try to pry the ring free (but beware of slipping and cutting yourself; you may want to take precautions like for opening oysters), or heavy scissors or tin snips to cut it free; some people have suggested serated knives or a saw)
2. You can try to squeeze the cap enough that the threads will engage, but not so much that you crush it so tightly that it won’t turn. Most pliers will not work for this, and you need something that’s designed for small pipes or large nuts. I personally use ‘slip joint pliers’ (commonly known in the US by the brand name ‘channel lock’. If you have ones that are meant for grabbing hex head bolts or pipes, they’ll typically make better contact. A large enough nut cracker may also work. You could also try using a clamp to crush the cap so it’s more oval shape, but then using something else to give you grip to remove the cap.

Once you get the cap off, beware that it may not make a good seal, and you may want to transfer the contents to a bee bottle.

Your last option is worse than the other two, as it’s more likely to get debris into the contents: make a hole in the top of the lid. You ideally want to use some sort of a punch that won’t create small bits (like a drill would). for instance could try hammering a large, clean nail into the top. (Or start with a smaller nail, then switch to a larger one to widen it after you’ve broken through). If you have a ‘church key’ type can opener, that creates a triangular hole in a can, you might see if you can get it to grip enough to get the leverage needed (unlikely, but worth a try), or hammer it in. You might still need a nail afterwards, as some of these lids have a plastic inner lining on top.

And if you use the third one, you will definitely want to transfer the contents to a new container… and maybe strain it, too, or let it settle for a while don’t pour off the last half inch (in case any debris sank to the bottom), but also watch for any they may have floated to the top.

Answer 6

I used a knife to saw off the parts joining the cap and the ring.

Answer 7

Put a towlette for eyeglasses over the cap and twist. I keep them to clean my phone, sunglasses, and radio dial in my car!