Older Cleavers - Anyone Know Anything About These?

I recently bought these two cleavers at an antique/flea market. I don't have any knowledge of cutting tools or cleavers and was hoping someone here might know something about these. I couldn't find much online so where else would I ask but here?:)
The larger one is marked Foster Brothers / Solid Steel / 2190 , has 3 rivets and is about 15 inches long. The smaller one is marked with a stamped USG between the first two of three rivets. The handle is leather. On one side of the blade it is marked USA and on the other what looks to be either the number 11 or the letter H, with Chicago USA underneath in a semi-circle (small lettering).
I'm sure they are not of any great value, but was just wondering about their age and who might have made them. And if anyone can tell me how best to sharpen them, that would be great as well. Currently they are pretty sharp and I must say that the smaller one made quick work of two chickens I was chopping up this morning.
Any information anyone can give me would be greatly appreciated. Thanks!