Were you inspired by Nancy Reese's presentation on using KLAS to track your consumables? Maybe you'd like to keep statistics on how many printables (such as BARD instructions or magazine listings) you send out each year, but don't feel the need to keep track of how many you currently have--since you just print more as needed.
For just this situation, it is possible to designate "unlimited" consumables by setting the "number in inventory" to a question mark.
So long as that question mark is there, KLAS will assume that you have the item in stock and will assign the consumable whenever it is put on Reserve for a patron. To stop it from going out, you could either change the number in inventory to 0, or update the bibRec Title Status to something other than Active.
Do you track any of your consumables in KLAS? Do you have any questions about doing so? Ask away!