Yes! The sponge technique takes a little practice to get consistent results, but it works well (at least for small boards), and lets you use microscopic amounts

Yes! The sponge technique takes a little practice to get consistent results, but it works well (at least for small boards), and lets you use microscopic amounts of etchant, which is good for cleanup. I find it’s especially good when trying to do relatively small traces, because you get such fine control over the process. (I have to say though, nowadays I’d usually rather wait six days for JLCPCB to do it for me.)