silver deposit on blue glasses. Mexico?

These belong to a friend and I don't have additional pictures. They came from a gentleman's estate that had a lot of things from Mexico but also South America. There are 6, with three more just the same as these. They are pretty large and would guess they hold 10-12 oz. Maybe 4" tall and almost as wide at the rim. I can find smaller blue silver deposit glasses but nothing this large. I am guessing the stylized birds would be the key to origin. Age? Worth ebaying? Target price guesstimate for the set of 6 - $30.00? $60.00? ???? Should the silver be lightly polished?

 

Maybe Peruvian based on pre-Columbian bird depictions?

Found this bowl that is represented as Nazca.


This is Lambayeque from Northern Peru.

 

I think getting closer ..... Site with vintage Peruvian jewelry that has a pelican very similar to the first bird on the left of my glasses. (pictures are protected so can't post them here)

http://imageevent.com/junetownsend/glaffiinspiredvintageperuvianworks;jsessionid=0qkn1yhg53.camel_s

 

I think these are probably Peruvian. Any thoughts on my other questions?

 

silver here should be cleaned not polished ...imo...

 

Sunshine Cloth.