If you google " lead testers", you will find a variety of machines, and prices available. The Cabin Tree tester is simple to use and fairly cheap. Others are designed to be used in a reloading press. If you are not reloading modern cartridges, you won't have such a press on hand.
IN buildings in rural areas, you might still find all lead weights used in window sashes. The iron ones became Required by early building codes, like IRON pipe, to protect the Iron worker's Union, and preserve those jobs in hard times. Such codes were passed in the big cities, like Chicago. It took a lot more time before these items became common in rural construction, too. When old buildings were torn down, the windows, glass, and frame and sash, were often saved, repaired, and used in the new house. You might find weights that have been used in several houses over their life time. Farmers built new homes when needed, and didn't have money to spend on New anything that was not absolutely necessary. Its still done that way today. I have friends who replaced an old, Clapboard farmhouse they were living in by first building a modern kitchen addition to the existing home, then building a new house next to it, on one level, before tearing down the older house. I don't know what if anything was saved in the demolition, but knowing Ron, I suspect that anything that someone in the family could use Was saved. I am sure the new kitchen appliances in the add-on were transferred to the new home, as were the toilets, and sinks.