Plasma ball purged out/remedies?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jolyon Vater Cox by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>

I know that this may strictly be "off topic" but since plasma globes were 
recently mentioned on the list I'd like to say that
I have had a such a globe for three or four years and recently the display
has become very thin and hazy -
it used to have bright lavender (argon?) arcs terminating in red (neon?) 
pads over the years these have become less bright now there is just a 
purple glow around the central electrode.

I understand that with time and use these globes "purge out" i.e. they lose 
their gas fill as the gas ions from the high voltage discharge are 
gradually adsorbed into the glass (with low pressure there can't be much 
gas in the globe anyway)

So I am looking for way to re-juvenate the globe to restore original 
quality of the display.

I have noticed the display is quite bright when it is first turned on -then 
it slowly thins out; it is also quite bright when it is switched to "audio" 
mode when it flashes brightly in sympathy with reasonably loud sounds, 
especially percussive noises.

Is it true that the globes have a trimpot in the base of the unit that can 
be accessed with a tool to increase the intensity of the discharge and 
"release more gas"
-I am a bit dubious as to how this reasoning works as surely increasing 
discharge intensity will cause remaining gas to purge out even more quickly 
-am I wrong on this issue?

Or will the globe actually have to be refilled- only,other than 
replacement,this really seems like the worst possible scenario as it is 
radical surgery; also I live in the UK where such facilities seem to be 
scarce or non-existant- who might provide such a service?