Hi everyone. I spent about 48 hours trying to depopulate 500g of these clean cut circuit boards by doing a standard AP solution with 31.45% muriatic acid and 2% HCl in a 3:1 ratio respectively. I poured muriatic acid onto the circuit boards until the acid covered the top boards by about 1 cm, and then added 1/3 of the volume HCL I used of Muratic acid. But I can't even get a quarter of the boards clean after trying to run an aquarium pump through. Could someone give me a suggestion?