ewww. Citrus soap will do it. No need for the heavy chemicals and horomones.
True, flushing the plant for a couple weeks will remove the bulk of many things you apply during growth but, no method removes 100% of whatever you use so it is always wisest to use the most natural prducts you can find.
You will be smoking some amount of everything you apply.

Try out the grow forum for tons of great info. And, in future maybe ask before you act if you are unsure.

happy growing!

peace.