I keep the unopened bottles in the freezer and only purchase the smaller bottles, because once opened and in use, the cyano does seem to deteriorate in the bottle. It seems to be a bit like mustard – they make their money from what is not used.
So, in practice, depending on the model in hand, I will open a new bottle, whether it be thin, medium or thick viscosity for that model’s construction rather than use an ‘old’ bottle.
Also, the named branded ones do seem to be better than generic unnamed ones and I have found that with some cheap versions, the thick type is not really thick.
Having said that, they all stick your fingers together very well!
Paul Freshney
Editor of MB.