Well, it's not really a detergent. It's more like Oxy-clean. The thing about it that you don't really need to scrub to remove residue. Mix it up, leave it sit in contact with whatever you're cleaning for 12-24 hours and oxygen will remove whatever is caked on. You can give it a good scrubbing afterwords if it still needs it.
Starsan is a strong acid concentrate but when diluted is perfectly harmless. I love the stuff. Find yourself a bucket with a lid and you can save it from batch to batch for a while. I mix 2.5 gallons each time and use it for a few batches before dumping.
I hate Walder Frey...