Honey locust makes some beautiful wood, works similar to red oak but a bit harder. When my tree guys bring locust it is under the condition that any thorns have been removed before it gets here. As far as metal in logs from urban areas, it can happen, usually in the butt log. I have heard of sawyers who completely reject any residential tree and, for me, that is a bit harsh. I primarily mill urban logs (KC Metro suburban/rural area) and I did a study of how often I encountered metal when milling. Last year, in the first 500 logs I milled, I only hit metal in 19 logs, a mere 4%. In almost all cases, I charge a $15 fee for hitting metal and in most cases I was able to clean, reset and sharpen the blade. Blades that cut through most nails, fencing and wire, even a railroad spike, are usually recoverable. Deck screws, hardened chain, and ceramics like insulators and armor-piercing bullets, usually mean the blade is trashed.