How would you modify a caffeine extraction experiment if toluene was used as the solvent?
After the toluene was evaporated to leave the caffeine behind, I would stir and re-dissolve the caffeine powder back into a warm water solution and to wash off any traces of toluene. Let it sit in a separator funnel until the toluene floats to the top of the water layer and then drain off the water caffeine mixture into another container and discard the very top layer containing toluene. Re-evaporate the water mixture, preferably with vacuum distillation to keep the temperature low and speed evaporation.
