API's NO2 (nitrite) reagent stains the tube

[Trouser Cough]

I normally let the other test tubes dry after a good rinse but the blue color from the NO2 reagent stains unless I leave the tube sit in water for a couple days and then give it a serious rinse.

Am I too picky about this stuff or do any of the rest of you have a trick you use to minimize build up of stain? Any of you use a test tube brush?

 

[duanes]

One of the best ways to rinse is to use DI water, because it is devoid of minerals that can help retain reagent stains.
I usually rinse each vial 3 times between any test.
DI water can usually be found inexpensively at grocery stores, and so little is needed to rise a a couple mL vial, (if whatever you rinse with retains reagents) it might be prudetnt to use the DI water.