Micro in a high muggle area
This is a historical site that also has a great view. While learning about the history of the area you can get a smiley and practice your cache replacing skills. The cache is somewhere a muggle could easily think it was trash if it isn't hidden properly so PLEASE REPLACE AS FOUND OUT OF SIGHT.
If you find the container and it is too wet to sign take a picture of yourself with the container and the monument as proof of find.