No, not alcohol, Toyota coolant !
I bought a 1L top-up bottle of Toyota (red) coolant, but try as I might, I couldn't get the lid off. Feeling rather embarrassed I phoned up the Toyota parts dept where I'd got it from to ask what the secret was, and they tried with their own bottle and struggled too. I started to feeling not quite so bad, especially when they said that they got a lot of calls about these bottles !
The instructions make it look like you have to press down and twist, but that just didn't seem to work, no matter how hard I tried.
At the other end of the phone, one of the Toyota guys took the bottle and bashed it top-down into the floor. Apparently this worked, I tried it on mine and it cracked the problem for me too. Looks like there's a seal or something that's difficult to break, I think the diagrams on the top of the lid are showing that you need to hit the lid, not just press it down.
Anyway, just thought I'd share my experience here in case others come across this.
My coolant expansion tank was empty, so I've topped it up now and will keep an eye on it.