Answer:
What cleans as it gets dirty only to get clean the more you use it?
Maritime marauders
What goes up let's of a load and come back down
When is 1500 plus 20 and 1600 minus 40 the same thing?
Ambitious people will climb the social version of this contraption.
I touch the Earth, I touch the sky, but if I touch you, you’ll likely die. What am I?