@GamePhysics - Detecting Player Inventory

PREREQUISITES:

	/scoreboard objectives add hasBONE dummy

MECHANISM:

	http://i.imgur.com/VqqbTjj.png

COMMANDS:

1. Sets player scores to 0 for 'hasBONE'. Required to do it this way since players are not automatically tracked in 1.8, and scores are being reset at the end.

	/scoreboard players set @a hasBONE 0

2. Sets player scores to 1 for 'hasBONE' if they have the bone in their inventory. This separates those who has bones from those who don't.

	/scoreboard players set @a hasBONE 1 {Inventory:[{id:minecraft:bone,tag:{display:{Name:"Custom Name"}}}]}

3. Gives players the bone if they don't have it.

	/give @a[score_hasBONE=0] minecraft:bone 1 0 {display:{Name:"Custom Name"}}

4. Sets item entities 'hasBONE' score to 1 if their item is the custom bone.

	/scoreboard players set @e[type=Item] hasBONE 1 {Item:{id:minecraft:bone,tag:{display:{Name:"Custom Name"}}}}

5. Kills those items that has that score (so only the special bones will be killed)

	/kill @e[type=Item,score_hasBONE_min=1]

6. And resetting the 'hasBONE' objective to prevent clutter from item entities being tracked.

	/scoreboard players reset * hasBONE