Steve,

The natural oils on your hands are acidic..... I cannot remember to what power though.

Look down the page to "sebum" & composition.  http://en.wikipedia.org/wiki/Sebaceous_gland#Sebum

When taking my soil tests I have made a habit of using nitrile gloves to make sure I do not accidentally skew results.

The same for taking tissue samples. Usually it is very hot & don't want the sweat running down my arms to affect my samples. (notice the gloves on van dash).

(Harvest 2010 100 (Large).jpg)

(summer tissue sampling 2011 029 (Large).jpg)

(spring 2010 101 (Medium).jpg)

(spring 2010 103 (Medium).jpg)

Harvest 2010 100 (Large).jpg (84KB - 45 downloads)

summer tissue sampling 2011 029 (Large).jpg (86KB - 62 downloads)

spring 2010 101 (Medium).jpg (142KB - 51 downloads)

spring 2010 103 (Medium).jpg (134KB - 42 downloads)