Supplementary Table 4: Average absorbance of each sample from the low-resolution mid-infrared reflection spectrometer.

Abs average 1 2 3 4
Upland cotton 1.31 1.31 1.39 1.41
Pima cotton 1.26 1.24 1.31 1.37
Oil on cotton 1.52 1.5 1.59 1.64
Grease on cotton 1.52 1.47 1.67 1.71
Bale twine 1.06 1.04 1.13 1.11
New module tarp 0.78 0.79 0.82 0.81
Old module tarp 1.54 1.51 1.5 1.59
Hard green 0.87 0.84 0.92 0.88
Black plastic 1.91 1.94 1.91 2.57
JD module inner 0.39 0.43 0.32 0.28
JD module middle 0.33 0.34 0.38 0.34
JD module outer 0.41 0.41 0.47 0.42
White shopping bag 0.5 0.54 0.47 0.46
Color shopping bag 0.78 0.82 0.74 0.76
White bale bag 0.87 0.85 0.92 0.86
Color bale bag 1 0.97 1.11 1.04