gunk

So I have a 2nd hand filter, it has greyish white stuff gunked to it. We want to give it a good clean before using it and rid all the spots. Any suggestions? TIA

I just set up a small DIY CO2 system yesterday, and when I was looking at it today the airline is full of gunk. It looks like animal fat, just in yellow. Is it supposed to be like that? What have I done wrong? How can I fix it?