[movies]

Yeah, that probably still applies.  I was trying to come up with a way to shift the aqueous ammonia/ammonium equilibrium to make it more basic.

[billnotgatez]

What would be the best way to increase the concentration of ammonia in solution without heating it. Use a non-reactive desiccant???  

[Tetrahedrite]

I think you are all missing the point! Ammonia is a weak base and a lot of it will have to be used to increase the pH. The second point that I'd make is that alkali metals eg K, Na are a common component of clays and glasses and thus the small quantity of inexpensive sodium hydroxide required to raise the pH will have no perceivable effect. Why stuff around with with a volatile, expensive, weak bases when you don't have to?

[billnotgatez]

What about calcium hydroxide (slack lime) or calcium oxide (lime)?  I hear they are used in acidic soil. Soil is a close relative of clay.

[pizza1512]

Experiment...