A good retriever might locate it. I taught a lab to sniff out firearms in less than 15 minutes. I believe, he keyed on the smell of the oil. My hunting dogs have brought me things I had lost over years without any prompting. The dumbest one of the lot, a Pointer, retrieved to me the transmitter for the shock collar, which I dropped in a section of CRP. I did not even know it was missing until she comes running up with it in her mouth.