I didn't get what you mean, but here is what you need to do.
[trigger=My Trigger]MyTrigger
Events
Unit - A unit Acquires an item
Conditions
And - All (Conditions) are true
Conditions
(Hero level of (Hero manipulating item)) Greater than 10
(Item-type of (Item being manipulated)) Equal to Claws of Attack +15
Actions
Hero - Drop (Item being manipulated) from (Hero manipulating item)[/trigger]
This will drop the item if the item is Claws of Attack, and if hero is greater level than 10.
Hope that helped.