I just did that last night:
Okay, first you wash it with soft soap. Rince it for a few minutes until the suds are gone and it doesn’t feel slippery. Dry it with a towel or let it air dry. Put it under a bag of sea salt for four hours. Lastly, Let it sit under the sun for four to twelve hours in the sun or moon lite.
Hold it in your hand and believe you are putting all your energy into it.
This isn’t an electric car you can plug into a recharging outlet.
It’s your stone, put your spiritual/psychic imprint on it. When you feel drained or feel like the stone is about as strong as it can be, then you’re done.
Cleansing the stone in a water bath of sea salt and then setting it out to rejuvenate in the fading afternoon sun during a full moon will cleanse and recharge your precious Amethyst. It is preferable to set it on some green grass and allow the stone to soak in the elements overnight. A windowsill will work but allowing the stone to reconnect with where it came from is best. Do remember to never overexpose your Amethyst to sunlight or an acid environment, as both are detrimental.