All good information above.
I have found a solution that is both practical and inexpensive. I use Zinc Oxide paste (40%), usually sold as Diaper Rash Ointment. This can be found everywhere and is very cheap. It is better than Vaseline because it will not stain your clothes. It does not sweat off, but will come off in the laundry. It is a good solution to any chafing problem.
Dan