In order to maintain their performance, conventional Bottle Top Dispensers are always rinsed once they have been used with strong or hazardous reagents. For this, the instrument is dismounted from the reagent bottle and then put onto another bottle containing distilled water. Once it has been rinsed, it is remounted back onto the reagent bottle.
Depending on the application, the spring in the outlet valve is either made of Platinum Iridium or Tantalum. Platinum Iridium is not suitable for Hydrogen Peroxide whereas Tantalum has limitations with Sodium Hydroxide. Because of this spring metal reactivity, the user has to procure different kinds of Bottle Top Dispensers for different applications which just adds confusion and proves to be an expensive proposition.
The spring also offers a surface for deposition of chemicals. This results in a piston jam, thereby compelling the user to repeatedly clean the valve, or replace it altogether.