WD40 will blast the crud away if you flush it with it. It won't lubricate it.
Lithium is what is recommended but it grabs grit and dirt from the road and stick thing us rel good.
I use silicone to blast it clean and to lube them.
Have to clean and lube them after any lengthy trip or storm.
There is one maker, Stromberg Carlson, I think, of steps, that look identical to the ones on our MH and I assume unpowered models too, that have grease seals and don't have to fool with them near as much. Cost more of course. More than you asked for I guess. Just my 1/2 cent worth. Your mileage may vary.