Originally Posted by SAT Lawyer
There are luggage lockers throughout Schiphol Airport.
The best place to sleep is near the meditation center and the KLM Crown Lounge (no. 41). Just head upstairs past the casino. There are some great designer chairs that resemble business class seats in a public area there.
I believe that in order to sleep in this area the OP would need a boarding pass for his onward flight... which he may or may not be able to get the evening before departure.
BTW, welcome to Flyertalk,
for4rest2000