Brown Gunk Buildup In PC Casing!

[Coolbro458]

I have no idea what this stuff is ! It's been in my case for a year and I want to know how to remove it and or what exactly it is!

Buildup Of Gunk In PC https://imgur.com/gallery/2XufL

 

[CountMike]

Something was probably spilled in there (Cola, coffee ?), try steel wool.

 

[The Paladin]

lick it is it sweet ? sour? tart ? look under motherboard do you see similar residue ?
scour pad with windex or mr clean