From our experience at BRC Hardware, we use a wax based lube such as white lightning as it won't collect playa dust. That seems to work the best and does work wonders on things like zippers also. We recommend against WD40 for various reasons and although it will break stuff up, it tends to collect dust and then you have well lubricated sand in your metal bits. If you don't have a wax based lube, we recommend just using soap and water to wash the chain down to bare metal. Playa by itself will just crush, turn to powder and fall off and even act as a natural lube to some extent.
8 and Rod's Road in 2011