Using talcum powder on your drysuit?
Then here’s a caution. Diver magazine
reports that a 34-year-old English diver
died when his drysuit inadvertently
inflated, sending him nearly 60 feet to the
surface in 30 seconds. He suffered cardiorespiratory
failure.
The cause of the stuck valve? A buildup of talcum powder on the
  inside of the drysuit inflation valve and salt deposits on the valve stem on
  the outside. The deceased had borrowed the drysuit, which was of a brand
  he was considering purchasing, from a friend.  
There are lessons aplenty here. The only effective way to deal with a
  stuck drysuit or BC valve is to disconnect it from the air supply (in this
  case, venting the suit’s neck seal would not have been sufficient to arrest
  the rapid ascent).  
Furthermore, carefully service inflation devices and valves whenever
  you’re having your regulator serviced.  
And, if you’re going to borrow equipment, check it carefully before
  you use it — even if it’s from a friend.