i suggest soaking your buds in ice-cold water for about 60 mins, drying, THEN performing your solvent extraction. You can soak your plant material in an ice hash bag, so that any trichs that fall off are caught by the filters. The water will leach out a lot of the chlorophyll. After you have your extract (I suggest using hexane, as it's fairly selective and evaporates very cleanly, or chloroform, because it's the most efficient solvent for thc. always lab-grade chems!) filter it through activated carbon. You can get it at the pharmacy, its used for food poisoning, diarrhea, and some other stuff, and it's very common. It absorbs many impurities, including some of the leftover chlorophyll. What you should end up with is fairly potent, dark red oil.
If you want to go a step further, you can get some petroleum ether from the pharmacy or dry-cleaners. Dissolve your extract in ethanol or methanol, add an equal amount of petroleum ether and about the same amount of water. Stir it for a good 15 mins, then let it settle. The liquids will form three layers. You want to siphon off the top layer, containing the ether and cannabinoids, and evaporate it to leave yellow-red oil.
If you feel all mad-scientisty, you can also isomerize your oil by dissolving it in methanol or ethanol, adding 1 drop of concentrated sulfuric acid (hydrochloric might work), and refluxing for several hours. The acid is then neutralized and precipitated, and the extract is recovered by evaporation. You should look up the specifics yourself, i haven't done this procedure myself. This converts a lot of the inactive cannabinoids into active one, and makes your oil much more potent.
The only way to make it even more concentrated is through preparative chromatography. Acetylation could also make it more potent, but i don't know much about that...
So there, that's a bunch of techniques to purity your extracts, ranging from simple to more elaborate. I hope you find some of it useful, and as always, be careful with chemicals, and do your research!
