Vulcanite stem tenons can loosen in the briar mortise. In general, one heats the vulcanite to soften it, and then expands it to fit snugly again.I currently use boiling hot water (microwaved in a small glass container) and put the tenon in for 1 minute. I then push a tapered pick into the airway a millimeter or two and let the stem cool. I bought a set of picks at Home Depot. I also found an icepick at Walmart that works. One can also use a candle or non-torch butane lighter to heat the stem. Another approach that has worked for me is to heat the tenon and then push it gently straight down on a heat safe surface. This creates a bulge that tightens the stem. As always, start slowly and if you expand the stem too much, sand it down to fit. I once tried sand in a crock pot to heat the stem, but the sand didn’t get hot enough. Recently, I came across a stem that needed more heat to soften, so I purchased a heat gun pictured below. I used the low (250C) setting, holding the stem about an inch away for 30 seconds. This seemed to do the trick.