http://www.renderosity.com/mod/forumpro/showthread.php?message_id=3810107&ebot_calc_page#message_3810107

This was some time ago, I post a dirty sweaty skin there.
Take the second one of my examples.

the cloud node is for the "dirty" part.
Leave the cloud out for "just sweaty".

See that I put Specular at WHITE and 0.5 in this example.

Try, test, with your skin texture.
They are all different so you"ll have to test a bit.

Click to enlarge the picture

Happy Posering.

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!