Weapon Cleaning Kits are clustering around the three villages that spawn hunting loot. They will never spawn anywhere else. I also have them set to military and police as well, but they never spawn there.
I would find a ton of the cleaning kits in those three villages.
Here is my types for the weapon cleaning kit
<type name="WeaponCleaningKit">
<nominal>10</nominal>
<lifetime>28800</lifetime>
<restock>1800</restock>
<min>7</min>
<quantmin>25</quantmin>
<quantmax>100</quantmax>
<cost>100</cost>
<flags count_in_cargo="0" count_in_hoarder="0" count_in_map="1" count_in_player="0" crafted="0" deloot="0"/>
<category name="tools"/>
<tag name="shelves"/>
<usage name="Military"/>
<usage name="Hunting"/>
<usage name="Police"/>
<value name="Tier2"/>
<value name="Tier3"/>
<value name="Tier4"/>
</type>