They were woven into fishing nets to keep them afloat; especially in the Far East. On rare occassions, they wash up on the shores of our Northwest. As I said they are highly prized, and should not be confused with 'Target Balls'.
These floats also show up on the East Coast of North America occasionally - the one pictured here I picked up on the shores of the Bahamas 20 some odd years ago - these are said to be from Spain or Portugal.
Hi Sam, I was in a shop in Brunswick today where everything was outrageously priced[:'(] You might know it, it's on the left headed south on Pleasant street just before you leave town. But anyway, there just so happened to be a dark amber float with a 'pontil' that had a very vague shape of an anchor on it. It didin't have a price tag and I think I caught the owner by suprise when I asked the price. She said $6.00, and I said I'd be back. I don't know anything about the value of blown floats, this one was fairly crude, and the closure/pontil looked a lot like the green one David posted above. The anchor shape was not stamped, it appears that while the glass was still molten, the maker 'dribbled' the anchor shape. Should I go back and get it for the $6.00 she's asking?
I don't know how floats were actually made but they are interesting to look at - like Dave said, I'd offer a little less and see if you can pick up the amber float.
I'll try again on posting the pic of my float - Sam