anyone use canned hop extract?

A buddy gave me a can of hop extract, but I have no idea how to use it. I've always used real hops. It's a little bigger than a tuna can and says "Columbus 15.0 % alpha"

If anyone knows how much of this stuff is equal to an ounce of said hops, please let me know. Thanks.

It really depends on the extraction process. Is there any other information on the label? If not, what brand is it?

there's no label or brand on the can. I think it's bulk stuff for commercial use. here's what is printed on the top of the can:

COLUMBUS S CO2
15 0 G ALPHA
CROP 2010
10328102

Feels like the can contains a tarry substance. It's a gold can a about the size of two tuna cans.

Here what I have read
KgA = BU x Hl / 3500
Where:
KgA = Kg of alpha acids to add in the brew kettle (KG= 1000 g)
BU = Is the desired amount of bitter units in the finished beer
H1 = H1 of finished beer (Hectolitrer = 100 liters)
Use rates may vary depending on the brewing process and the desired hopping level

Plug what you know into the formula Bittering units x liters of beer divide by 3500 and it will give you how many KG of extract then multiply by 1000 that will give you grams to use. Since you have 15 grams in the can you can then figure out how much to use.
If formula says 1.5 grams then use 1/10 of the can. 15/1.5.
Or you could just trade it off for say a couple oz of hole hop amarillo?

Thanks, I will try this formula.