Oooh, I want to collect and test it now! DH and I decided to apply our brains to this one and we think it may well be slightly acidic, as skin is slightly acidic and the fluid would need to be what's best for baby. I now want to collect a few samples and pH test them LOL. But only corrosive if you don't clean it up, I mean even water is corrosive over a long enough period of time (see cliffs et cetera for proof).