I am no expert but this is what I do.. I just use a high proof alcohol to clean the brick then insert a q tip covered in wood butter after. So the process goes, warm water on a q tip, then go through again with a couple of q tips with rum, vodka or everclear on it. Then another q tip of warm water, then a q tip or two of wood butter. Run the q tips through the airpath and around the bowl, yeah the alcohol will start to dry the wood a bit.. but then when it's dry; it absorbs the wood butter very fast. This is the only way I was able to get any of my bricks clean enough for my liking. I have OCD and like things brand new lol.. kinda hard with the brick but this method keeps it clean enough