I've only been hiding caches a little over a year now, but so far none have come up muggled so far that I know about (knock on wood.)
When I hide a cache I always try to think in terms of the location. For example, if a cache is an area that is frequented by muggles I'll often try to move the cache to an area that is away from the most common path of travel. For example, one of my caches is on a hilltop that is frequented by hikers, bikers, ATVers, snowmobilers and even partying folks once in a while . . . while I wanted to bring geocachers there for the view I didn't want my ammo can to go MIA so the actual cache is located a bit downhill in an area that is not prone to geo paths (stone wall) and most muggles would never wander into that area.
In addition, I try to avoid using the dreaded geo-stick piles to hide the cache container whenever possible since there are few things less natural looking in nature than a pile of perfectly stacked braches. I often will look around an area and try to think how I can incorporate the surrounding area and terrain into the hide . . . i.e. stumps, dead logs, low-lying areas.
I think picking the right container is important. While I love to use ammo containers I have used micros in a few cases. In the cases when I have used micro caches I did so since the cache was in an area frequented my muggles where a large cache container would be difficult to hide easily without folks noticing. In general, however, I have tried to use ammo boxes since the areas I pick are usually good spots for ammo boxes and the ammo boxes with their natural olive-color seem to blend in pretty well . . . on occasion I have painted them black though when the black color would work better for camouflage.
Finally, I try to check in on my caches once in a while to make sure they are where and how I placed them . . . it's a simple concept, but for some reason some geocachers have a problem with the concept of leaving the hide as they found it. I can't tell you the number of times I've checked a cache only to find it hidden with the dreaded pile of geosticks or in some other manner that was not the way I hid it. In addition I check in on these caches since things change . . . i.e. one of my caches was hidden in an out of the way corner of a park . . . and within the last few months a trail was opened up right next to this cache so I had to make sure it was well hidden since there was the potential for more muggles to spot this cache now.
Obviously, none of these ideas are fool-proof . . . and in all honesty I suspect that one of these days a DNF logged by a geocacher will not be a case of a hard-to-find cache, but rather an actual muggled cache. I must also add that most of my caches are not in high density urban areas which I realize reduces the likelihood of the cache being muggled. Again, these are just my opinions.
P.S. Welcome to the geocachingmaine.org BBS!
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