I use cotton ear buds - the things that are plastic sticks with some tightly woven cotton fibre on the ends. Never to be used in ones ears, incidentally.
The IP alcohol I use is more like around 60%.
Cleaning each pin gently and methodically is tedious of course - perhaps at least a few minutes per tube.
This makes no difference to sound of course.. It is just prudent to remove any possible oxidization and any other possible contaminants like dust from an electrical contact that is just held into place (and reduces wear on the socket).
I don’t use any other cleaning solution. You shouldn’t mix your drinks.