Here are some wonderful trails:
I am NOT able to see any difference between con- and chemtrails. Every trail depends on so many physical parameters like humidity, temperature, speed
of the plane, particles in the exhaust - I simply don't think that you could present me pictures taken with (almost) exact the same parameters in
which I could see something which would be clearly a chemtrail or a contrail.
As long as these parameters aren't confirmed for every possible chemtrail, as long as that I will take every trail for a contrail. I know it's quite
impossible to present these parameters, but as is the claim to have seen a "true chemtrail".
Dustparticles on your veranda are no clue, they could come from nearby industry/agricuture/etc. They would really seldom drop near vertical from a
single trail above on your house, too many cross-winds, drift from the planes speed, etc.