Hi Jess, most crystals have their own energy and so don't need to be charged or recharged when being used normally. You can put them on a large bed of crystal to help cleanse them and then they will 'recharge' and rejuvenate just as we would if on holiday
Its probably more important to cleanse them and earth and ground them.
If using the crystal for really hefty crystal work, sometimes a boost may be needed and then moonlight or sunlight might help. You can also charge your crystals with reiki when using them in a grid, or layout so that they carry on sending the energy
