Dave,
Thanks for the compliment.
Yes. I have had the same earthen ware crock of stain for 20 years. Every time I finish a rifle I had some vinegar to the crock, stir it up, let it settle and decant off about half a cup of clear liquid stain. I have found that it is a good idea to add just one drop of Dawn dish detergent to the half cup of stain. It breaks down the surface tension of the water and helps the stain penetrate. I also wash the stock with warm soapy water (Dawn again) as part of my wood cleaning prior to staining. I whisker the stock, burnish it with a brush made of hemp rope real good before applying stain.
Best Regards,
John Cholin