Digging
Digging is a skill purchased like any other that allows you to dig holes in the ground and put or receive any items. It costs *5AP to dig with a shovel and *10AP without. There are 4 levels in a hole (shallow hole, hole, deep hole, very deep hole) and every time you dig you deepen the hole by one level. In beaches you can only dig up to 2(?) levels. You cannot dig in swamps, inside huts, in tunnels, caves or in the water. Each level can have **6 items, so on the last level there'd be **18(?) items. You don't need to fill the hole after each level when putting items in, as long as you drop 6(?) items or less. If you want to drop more than 6(?) items, you need to fill the hole and then continue dropping (assuming the hole was deep enough originally). Anyone can put items in an already open hole with the "drop into hole" button or fill them, but can't dig new holes themselves without the digging skill. You don't need to search to find items in a hole, but rather when digging in a spot where there are items to be found you'll get a message "you dig and find 2 bottles of rum and a knife." Also, there is no way to get any items you dropped in a hole quickly. You will need to fill the hole and then dig again. No XP is awarded for any actions associated with digging.
*There is some controversy surrounding this statement. (I'm not entirely sure if its true or not).
** I have tested this and found that there are 4 levels. Shallow, a hole, a deep hole and a very deep hole.