We can't stand bugs on our plants but hate using expensive and toxic chemicals. We've experimented with a lot of store bought sprays but have found the best recipe is this simple soap spray from SF Gate :
Soap and Alcohol Spray
Mix 1/2 cup of ordinary rubbing alcohol with 1 quart of liquid soap. The alcohol helps strip away any waxy coating on the mealybugs so the soap can penetrate and kill them. Wait 20 minutes after spraying, then rinse the plant with water. Repeat, if needed, every three days. Do not spray in direct sunlight.
Applying Soap Sprays
Pour mixture into a spray bottle or pump sprayer and apply to the upper and lower portions of leaves, plus stems and twigs or wherever mealybugs are congregating. Pump sprayers work well on large or multiple plants. The plant does not need to be dripping wet, but thoroughly covered. If the infested plant is a small, potted plant, you can pour the soap solution into a basin and simply dip the foliage into the mixture. If the insects are concentrated in specific areas, try soaking a rag into the soap solution and wiping it on the insects without wringing out the rag first. Except for soap-alcohol mixtures, leave the spray on the plant for about two hours and then rinse with clean water. This keeps the soap from drying to a scum on the leaves or from dissolving the foliage's own protective layer.
Test the soap spray on an inconspicuous part of the plant to be sure the foliage won't be damaged. Check the plant daily for about two weeks for evidence of distress, such as browning or curling leaves. Never use dish detergents that contain degreaser, nor electric dishwasher soap. Soap sprays work by smothering mealybugs and other soft-bodied insects like aphids and whiteflies, destroying their protective coatings or interfering with their nervous systems. Soap sprays have no residual effect; reapply at regular intervals as needed.
Extra Tip: Keep in mind mealy bugs should turn dark when dead, but won't fall off on their own. You can go in with and cotton swab or toothpick to remove the bugs, once they've been sprayed. Best of luck! Please let me know if you have any other questions!