Took Nothing, Left Nothing (or TNLN) is a term used in GeoCaching to describe when a GeoCacher succesfully
finds a cache and chooses to neither leave, nor take any of the booty in the cache. Many long term cachers
find little value or interest in the booty once they've logged some caches. It's more the thrill of the hunt
for most series cachers.
TNLNSL is another popular option when logging. This simply means Took Nothing, Left Nothing, Signed Log.