Years ago, I used the generic top soil bags as substrate for my indoor enclosures. One time I found a screw in the bag. Another time a piece of glass. So, I switched to coco coir, cypress mulch and sphagnum moss. I still buy those items to this day and have yet to find inappropriate materials in them.
I still occasionally buy top soil for outside though. Usually just to fill in small areas as needed. Recently, I found a strap of leather (or something like it) in the bag.
I still occasionally buy top soil for outside though. Usually just to fill in small areas as needed. Recently, I found a strap of leather (or something like it) in the bag.