[HAM] Oiling a JR-20

[Stuart]

I have a "B" chassis JR-20 and I know it has not had fresh oil in it for many 
years.  The cardboard tag attached to the reverb unit references a bulb used 
to fill the short tube to 3 1/4" from the top.  I have read that some use 
mineral oil in the tubes and others have used Hammond oil or even a mixture. 
That tells me mineral oil is probably ok.  Was there some kind of kit that 
came with the cabinet to fill the tubes? What I really need to know is what 
is the correct or preferred way to get the oil into the tubes?

Thanks all,

Stuart