You're right. Crystals are great, but then you have to remove the energy from the crystal. Soaking them in salt water works well but this may damage some gemstones. Othertimes its good to bury them and leave them for a week or two, then dig them back up. (Be sure to mark the spot so you don't lose it).
Transference is just moving a particular energy (in this case pain) from one vessel (your body) into another (a rock, crystal, potatoe, onion, meat, etc). If you need to transfer an illness or chronic pain, organic materials that rot are perfect because as it decays, so does the illness/pain. Be sure to bury them deep and away from your home. It could attract animals or cause a stench.