Unexpected surprises while thrifting

  I am in a bit of a quandary.

While thrifting I came across a garbage bag

with yarn, an knitting instruction booklet and

what I thought was an unfinished sweater.

I bought it all for $2 just so I could reuse 

the vintage Spinnerin wool yarns.

The sweater is actually complete.

And gorgeous, with cables all down the white.

I'd hate to take apart someone's handiwork,

but it has most likely been bagged up

for over half a century.

What would you do?

(PS, if you are interested in vintage knitting patterns,
I have quite a few books in my Etsy shop)