I just made my first batch of Silver thiosulfate.
I bought some on ebay where it comes as a 2 part, sodium thiosulfate and silver nitrate. I had to get a microgram scale to weigh them out and wear gloves. However neither is super dangerous, sodium thiosulfate is used as a medication and silver nitrate is used as an antiseptic. But still, don't want to make it a habit to come in contact with them.
I guess my batch is gonna be a bit strong because my bottle can only hold 250ml of water instead of 300ml like the batch was meant for. Oh well. I'll just go a little light on it.