Subject: Is there any solid evidence for 'chemtrails'?

Chemtrails, or chemical trails, are what some claim to be a chemical spray 
coming from jet planes.  The name is a derivation of contrail, short for 
condensation trail. Contrails do come from jet plane exhaust, resulting 
from condensation on exhaust particles essentially creating a long, skinny 
cloud. Contrails a very common and highly visible when upper air weather 
conditions are right.
Chemtrail devotees think that CONtrails are at times laced with chemicals 
or viruses or something sinister, becoming CHEMtrails. They sight an 
increase in contrails and weblike contrail patterns as evidence.
My question could be written: What is the best way to debunk what appear to 
be ludicrous theories about chemtrails?
Thank you

Re: Is there any solid evidence for 'chemtrails'?