What is the proper way to clean narrow neck flasks?
Narrow neck flasks are best cleaned in labware washers with special attachments that have a spray nozzle that goes up inside the flask. It is very hard to successfully clean narrow neck flasks in a simple home dishwasher or a lab washer that does not have special narrow neck flask racks. The only way to do this is to presoak the narrow neck flasks completely submerged with all the air let out in a 1% Alconox or Liquinox solution prior to "washing" in the machine. Even this can fail if the other glassware cleaned at the same time has a large amount of residue on it which can redeposit on the narrow neck flasks and not be prevented from staying there by the anti-redeposition agents because there can be inadequate amounts of wash solution getting in to the narrow neck flasks without the special wash spindles.