yes, I think its great that you rescued that Mac.

maybe that floppy drive will still work, run a disk in and out of it… if the drive mechanics are sticky or jamming oil it.

i've personally never seen that much filth on a mainboard like that.

but that is ok take it to the kitchen sink spray it down with windex get the hot water rolling and used the sprayer and get all that

filth off there

I think you have a fun project on your hands there.

blow the hd off with a compressor.

Its ok the previous owner didn't appreciate it. I am sure once its working you will.