Salt and cramp, I suspect thats a myth, however I'll back my suspicion up with some decent evidence:
Serum electrolyte concentrations and hydration status are not associated with exercise associated muscle cramping (EAMC) in distance runners
M P Schwellnus1, J Nicol1, R Laubscher2, T D Noakes3 Br J Sports Med 2004;38:488-492
Interesting to note that hydration and cramp is probably also twaddle.
Also ingesting salt, licking your arms etc is probably twaddle:
Sodium ingestion and the prevention of hyponatraemia during exercise
Br J Sports Med 2004; 38: 790-792. doi:10.1136/bjsm.2004.014191
Fascinating to note that this paper showed that sodium levels dropped even when replacing fluid with a sodium containing drink going flat out against a lot of current advice, ie overhydration with any fluid is not necessarily a good thing.