Hi,MrAl:
You know batter. You need to post a pic.
I'll give you an idea. Two long boards with a hinge between them. The basics of a "can crusher".
take a nail, an "o-ring" and a step collar so you have nail, board, step collar, o-ring.
Do whatever you have to to get the right length and to secure the can.
Now, put the can in a zip lock bag.
Puncture the can through the zip lock. The "O-ring" should secure the grease and seal against the collar. I;m assuming not a whole lot of pressure inside the can. More like "shaving cream" type of pressure.
All of that is likely available at my local hardware store.
You might only have a tiny hole to deal with.
The hi-tech way, that costs more than the grease: https://www.grainger.com/product/GRAINGER-APPROVED-Side-Can-Tap-10U329
Who knows what the diameters are of your can or the tap.
What brought me there was what an R-12 can tap looks like. You might have one lying around.
That side tap thing looks pretty cool. Maybe make a sleeve and then drive a sharpened steel screw into the side throught the sleeve, which would gently puncture the can.
