Hello, You know, bottle typing is just like the "White Ware Wars" we had on Arch-L a few months back. Set six historic archaeologists on the same pile of glass and you will get six creatively different piles of glass. I have used Parks Canada for glass analysis, but when the opportunity came about to fund glass analysis I jumped on the opportunity to get a specialist in 20th century glass to examine tha thousands of artifacts I had recovered from a 20th century Army post. The U.S. Navy awarded the contract for glass analysis to Paul hampson. I do not have Paul's address here at home, but you can find it in the SOPA directory. If you do not have access to the SOPA Director, and shame-shame, you can write to Roberta Greenwood, Greenwood & Associates, 725 Jacon Way, Pacific Palisades, CA 90272; phone (310) 454-3091. Paul has been working for her on a collection from a 20th century site in California. I can't help you on the tin cans. You should track down Jim Rock at U.S. Forest Service at Yreka. He has done a lot with tin cans. Ron May c/o [log in to unmask]