I can't seem to find any, and my heads are in desperate need of a cleaning.
Go to any drug store and, if need be, ask the pharmacist for at least 90% (or higher) isopropyl alcohol.
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I suggest also appearing as deranged as possible when asking the pharmacist!
go to radio/electronic supply store. Most of the stuff in supermarkets is 70% tops.
I've used it, just not as good at cleaning.