I hated the thought of this when I was little, when I had a cut or a graze this was seriously the most painful antisteptic ever!! But as I've got older I've realised how good this is for spots!
Yes it stinks, everyone knows you've used it because you can smell it a mile off, but I can just about deal with that, especially when I'm trying to get rid of a massive beasty spot.
Basically what I do with this is I pop it onto a cotton wool pad and sweep it over the affected area (if you have already broken the skin this stings more than normal so beware!). If the spot is just red, LEAVE IT ALONE... as tempting as it is to try and squeeze the life out of it, please don't, I speak from experience and I now have numerous scars on my face from spots which weren't ready to be popped. However, if it does have a white head on it, you can do something about it as long as you're hygienic, which again is where TCP comes in.
First of all, wash your hands and then once you have wiped the affected area with TCP, I then suggest that you wipe your fingers with TCP to give you extra protection from reinfecting the open spot. Then using some tissue over your fingers, gently squeeze the spot until the lovely gunk has come out of it... then immediately after, with a fresh cotton pad, sweep some more TCP over it and hold it on the spot for a minute or so to make sure you have made it as antiseptic as possible.
I know you can get all these posh 'spot zappers' but 9/10 I've found that they don't really work for me and they are a bit of a rip off. I find that if I use TCP on a big angry red spot it will reduce the redness and swelling and make it more managable in terms of covering it up and sorting out any possible infection. And the best thing about this is that it's available pretty much everywhere; Superdrug, Savers, Supermarkets, Boots... you should be able to pick this up somewhere no matter how rubbish your local shops are!!