Discoloration on Mr. Driller PCB - What is it?

[sik-]

I haven't had any issues with this Mr. Driller PCB since I got it, but I was just curious what exactly this discoloration may be from.

 

[skate323k137]

Likely Flux residue from manufacturing, you can try 90+ percent iso alcohol and cotton swabs to remove it if you want, but I'm not sure if I would bother with the mess.

 

[sik-]

Thanks a lot!

 

[skate323k137]

No problem, have fun