Chop fresh comfrey leaf and place into the clean glass jar. If using dried leaf place it into the jar.
Pour the alcohol over the herbal material so that it is fully covering the comfrey leaf. The ratio of alcohol to fresh herb is usually 1 part fresh herb to 3 parts alcohol or, if using dried herb, the ratio is 1 part dried herb to 5 parts alcohol.
Place the plastic over the rim of the jar and tightly cap the jar with the lid. The plastic will prevent your extract from becoming contaminated with any rust that may form on the jar lid.
Shake the jar vigorously and place in a cool, dark place for 4-6 weeks. It will take that long for the alcohol to extract the active ingredients from the comfrey leaf. Be sure to shake the jar every few days.
Strain the alcohol from the herbal material after steeping the herb for the recommended time period. This can be accomplished by placing a strainer, lined with a double layer of cheesecloth, over a bowl and pouring the contents of the jar into the strainer. The extract will go into the bowl, and the saturated comfrey leaf will stay in the strainer. Gather the cheesecloth around the herbal material and squeeze all of the liquid from it into the bowl. Some of the strongest constituents are in this wad of wet comfrey leaf, so make sure that you squeeze the excess liquid from it.
Pour your fresh salve (comfrey extract) into individual storage bottles for later use. Be sure to label and date your jars.