Grinding tools. a. Cordless drill (with rechargeable battery) with stainless steel pestle with Teflon end that fits inside a 1.5 ml microcentrifuge tube (purchased commercially). For hard tissues, a stainless steel rod without the Teflon end can be used for grinding. More force can be applied to the sample because of the smaller surface area. b. Battery-operated grinder with disposable pestle (purchased commercially). c. Manual grinder fashioned from a small screwdriver that has been ground so that the end fits into the bottom of a microfuge tube. d. Manual grinder fashioned from an awl that was ground to fit the bottom of microcentrifuge tube. The wider handle distributes the force on ones hand more evenly.