Pluck dead, discolored and shriveled leaves from the plant with your finger tips. When dead or damaged, the leaves often come free from the main, brown plant trunk, called the meristem, when barely touched. These leaves can be composted or simply discarded, as they are of no use for propagation.
Snip off damaged, asymmetrical, overgrown or otherwise unsightly leaves as needed with a sharp clean knife or scissors. Sever the leaf low on its stem, near the meristem without cutting into the meristem. Pull the cut leaves from the soil surface and never let them decay in place on the plant or the soil as this invites disease.
Remove mature leaves for propagation purposes by severing the leaf from the meristem so that at least 1 inch of the leaf stem remains attached to the healthy leaf. Use a clean, sterilized knife or scissors to make a clean cut without introducing pathogens. The leaf stem can then be planted to root and develop into a new plant in a few months time.