I heard a story about someone who did a standard 1/2 kilo MHRB STB but couldnt get round to finishing the extraction for some weeks after the MHRB had been soaked in the NaOH solution.

When he finally got to the evap stage, the resulting evap product was very yellow and oily but also contained many squarish crystals that looked similar to salt crystals. Can NaOH leak into the naphtha given enough time, or has some other chemical formed from the lengthy period of contact? Is this salvageable with a wash do we think?

I cant believe that noone else here has left an STB for a bit longer than they first intended?

It is safe to add the naphtha. The NaOH dissolves in the water and raises the pH level while in the meantime destroying the plant material. Leaving it around for longer will dissolve more plant fats and additional impurities.

Just add naphtha as if it's a fresh extraction and re-crystallize with heptane to get rid of the impurities. And if you want to be really thorough do a solvent wash using some de-ionized water with a punch of sodium carb. The wiki has all the information on how to do a solvent wash.

thanks for your input, thats good news for someone i think