‘Bodhi’ seeds, which is a misnomer, are from a tree related to the Rudraksha (Elaeocarpus ganitrus) and not the Bodhi tree (being a fig tree, its seeds are inside a tiny fig, and are miniscule). The scientific name of this tree, native to Nepal, is yet to be determined.
The seed in the image shows the mark from the stem on the side, and a drill hole in the top of the bead.
Measuring, on average 10 – 12 mm. in diameter, bodhi seeds are dried, holes drilled, and are then strung into malas or jewelry in a process that has continued unchanged for millennia. Hard, durable, and really smelly when new, they achieve a pleasant patina from constant handling and make convenient meditation beads. They are a bit large for wear around the wrist, at least in a full-length mala, so most practitioners keep them for use at home or wear them around the neck.
Bodhi seeds are mostly hollow inside, and full of little bits of the actual seeds. They collect and hold viscous liquids very efficiently and as it turns out, the little fragments of seeds swell up and come loose inside the bead, further holding the aforementioned liquid in place.
I just spent a highly spiritual (not to mention messy) 45 minutes with an air can, blowing excess lemon oil out of 108 beads. I suggest wiping, not soaking, in similar circumstances.
Like so many things, it seemed a good idea at the time.