Maxwell cap filler plugs & oil

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

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Gary.Lau-at-compaq-dot-com>

I've been meaning to ask this.  I found several Maxwell caps at a flea
market  last year.  One of them is silent when shaken and I've been
using this with great results.  The others all "slosh" when shaken.
I've not yet used them and they appear to be unused.  They all have a
plastic screw that can be removed, presumably to fill or drain the oil.
Is it castor oil that is used in these?  Where can this be found?
Anything else I should know about topping them off?

Thanks, Gary Lau
MA, USA
 
>When purchasing Maxwells, (I have 3), you never know their prior 
>history, ergo you never know their remaining life expectancy. It is
finite. 
>Some have a plastic screw as a "filler plug"  these occasionally 
>leak during shipping or they leaked before shipping and weren't topped
up.