I'm reviving this TP thread, in a different direction.
If you don't use TP, move along, there's nothing to see, keep driving.
For the TP users ONLY, I was thinking about those fast food starbuck brown napkins, you know the ones that have printed on them "Made from 100% recycled paper"
I used them with reasonable success. The napkin is fairly large, so I can usually make 1 napkin last for 2 to 3 applications.
I'm guessing here, the starbucks napkin will decompose better or the same as white TP.
If an animal dug it up, the color of the brown napkin does not stand out as much as the bleached white TP.
Time warp history:
When TP was first factory mass produced during the industrial revolution, the paper color was newspaper greyish brown. The consumers were partially interested because it didn't convey the clean image. The marketing guys added bleach to the paper pulp for that bright white look. TP Consumers loved the bright white color even though the added bleach was an irritant. Now the paper bleaching is minimized and irritation is negligeable.
Now on the forum we are not so prima donna, and somewhat adventurous with testing. I suggest giving fast food / Starbucks napkins a try.
If someone does a biodegradable decomposition test, tell us about it, with no pictures.