cleaning electronics after watering

i open my ipod an cleaning it with destilled water, isopropylalcohol and a brush.

with this treatment on the flexcabel the 3 white, kind of foamy patches was destroid.

now i see 3 golden, oval spots / kontacts.

the reasen for the patches are ? only for fixed it on the inner shell or are the needet for isolation between the golden spots an the shell ?

are this patches essential ?

can i use some other (household)- material ?