As the title says, a toutch of vegetable oil in the bong will keep the glass clean much longer. METHOD - To a spotlessly clean bong add water and a few drops of veg oil into the down stem. Perculate vigerously until the oil is well and truly mixed throughout the bong. Empty, fill with clean water and use. I change the water in my bongs every day and do the oil thing maybe every 5 days or so. Also, the little bit of grime that does build rinses off pretty easily with detergent (excluding the downstem) I like clean bongs and I dont need to salt + alcohol clean them nearly as often as I use to. Hope this helps.
This 14 inch recycler was a real pain to clean, untill now. I've put well over an ounce of herb through this thing over the last week without an ash catcher. All I've done is change the water daily, and give it a bit of a rinse in cold water. It's still looking pretty clean IMO.
