It is made of copper as best as I can tell. It needs polishing, lots of polishing. Does anyone have any ideas as to how to make this go quickly. I have Mothers and it seems to be doing a fairly good job but is gonna make my arm fall off. Any ideas guys?

Brasso may work better on the copper.
One thing you want to do first is take it apart. That type of extinguisher uses a soda acid to generate pressure. If it spills on carpet or your clothes, it will disentegrate them.
We found some old ones on a demolition job and the guys (me included) decided a water fight with them would be fun. It was until we washed our clothes! They fell apart in the laundry!

The cheapest way I found to clean copper is with cheap tomato catsup. try it it waorks fast and does a good job.

I have one of those. I started on it, and quit after 10 minutes. I have been told to take it to someone that does that, and bite the bullet, pay them to do it.
I took it down from the attic last week, and thought I would get a fortune for it. I looked on E-Bay, and saw one's that looked brand new, polished to the max, going for $20-$35, top price.
If it does not have any sentimental value, I would donate it to the closest firehouse, buy one on E-Bay that is already polished like new, and use the elbow grease on your Vette.
My 2 cents,
Boatman