Spraying v. Non-Spraying?

[yao]

Never heard of spraying but I have heard of putting extract on a cotton ball and sealing it in a mason jar with the weed to get the same effect. Just put like a cardboard barrier inbetween the weed and the cotton ball to avoid direct contact.

nah, around here there's none of that

back to the spraying thing, anyone know anything about it?