What is the correct way to use the Zerostat?

I have yet to wear mine out after 30 years.

From the web:
This amazing little device known as the Zerostat Antistatic Gun is an antistatic "generator" which has numerous applications in any microscopy laboratory. Just squeeze the "trigger" of the Zerostat and a steady stream of ions is released. The "magic" comes from two powerful piezoelectric crystals and a patented compression trigger. Originally developed for removing dust from "vinyl" and before that, normal "phonograph records". In later years the Zerostat antistatic gun was discovered to have great applicability for use in a photographic darkroom to remove dust from film and negatives. After that, a wider range of applications came into being when people running SEM labs found out that it was also ideal for eliminating dust from critical samples or other critical surfaces when the dust attraction was being caused by electrostatic charge. Others have reported that certain insulating specimens, when treated this way, can actually be viewed (admittedly briefly) by SEM without the need to apply further coating.

Each Zerostat unit has a "two cycle" type of operation. When the trigger is squeezed, positive ions are generated and when the trigger is relaxed, negative ions flow. This means that it is possible to induce a charge on a neutral surface using the Zerostat. If the trigger is squeezed, and the Zerostat is removed from the surface before allowing the trigger to return to its original position, a positive charge will be induced. Similarly, pointing the Zerostat at the surface only for the release of the trigger will induce a negative charge

Also,
Hold the Zerostat within 12" (30.5 cm) of the surface or object to be treated. Squeeze the trigger slowly for about two seconds, to emit a stream of positive ionized air over the surface of the object. As the trigger is slowly released, a negative show of air ions is produced resulting in static neutralization. Repeat this procedure at several points across the surface of the object.

The Zerostat needs no batteries or electrical supply and unlike other antistatic products, the Zerostat contains no radioactive components whatsoever.

Important notice! Remove the ion indicator from the barrel before using the Zerostat Antistatic Gun to neutralize static charge. Ion indicator is for testing use only.

Caution! Do not use in an explosive or combustible environment.

An old trick is to point the Zerostat away while pulling the lever, then towards the brush when releasing. This gives the record brush a neg. charge and is quite effective for collecting debris. Best results occur by treating the lp while off the platter. Audphile's suggestion for grounding is good, try touching the TT's spindle with one finger and a grounded unit (amp's faceplate?) with another finger to neutralize system static.

...and don't do something foolish like press your finger on the tip of the gun to test if it's working, it hurts like hell.