Two zip-lock baggies. Nest them. Burp all the air out. Stash your clean clothes 20 feet into the woods from a highway sign, mileage marker, etc. Cover with branches and leaves. Maybe leave a discrete sign for yourself - crossed sticks, or a shiny rock, etc. Along trails, I'll tuck stuff under the decking of a foot- or highway-bridge.
I do stranger and more precise stuff than this all the time. If I need to essentially create a benchmark, I'll write in sharpie marker on a sign post or guardrail post, "20.2 feet from here". Two or three such data points or some pics on my cell phone and I can triangulate a location months later within an inch, even under a foot of snow.
Obviously, avoid any food smells on the bags.