if you research alot (like me when my brain wasnt fried)
captain jacks deadbug brew is great. It is a "safe soaps" + spinosad
spinosad is a bacterium found in an abandoned rum distillery on a carribean island or something; if i remember right.
things you might wanna do next time:: preventative maintenance, Intake filter ( need to have a big intake adapterto add a nice filter it is crazy how much crap it will filter)
what I like to do is use neem oil and deadbug brew alternatively at low applications only during the vegetative stage. remember organic things break down and your goal is to apply these organic pesticides early. every week after an application rate is per week i take half of that and rinse the foliage with clean water to get any residues,
technique when spraying is important. a spreader sticker is good to allow the water to be wetter.use a pump sprayer or a spray bottle depending on your size of ur grow.,
fogging is a more expensive and better method but what i do is spray the underside of the foliage first, rotating the plants then put them aside. after getting all the undersides of the foliage and stems* i now go over the top of the foliage of everything, to give it a final coat in case tops were not hit right. never doing a spray when the lights are on either...
your soil if not sterilized before using, will have all sorts of dormant crap in it. if you preventive spray it you will not have to worry about residues late flower. I also do a preventative layer of diatomacious(sp?) earth on the top of my soil just for gnats.
my point here is prevention is key. and if u really wanna reduce pesticide residue on your product is literally make a schedule on a calendar of what you want to do to preventative maintenance on your plants and give them time and rinsing of foliage to reduce any residues
sulfur is something I have heard about but never researched into . from what I understand it is the best but im not sure how that affects flowering buds