Originally Posted by Old NFO
At IAD they are "allowing" you to go back and put 4 oz contact solution in your checked luggage, or disposing of it; they are saying 3oz is the limit in the 1 qt bag.
I think that you have actually stated the rule: You cannot put a 4 oz contact lens solution in your quart bag but you can take it in your carryon if you declare that you have it as an essential medicine as an exception to the no liquids rule. Remember that it is all about form and not about substance and that should help.