Black patches on back of new motherboard

[boks]

I bought this new Z370 ASRock Fatal1ty K6 mobo. I did a post test outside the case with cpu, gpu, ram and got into the bios fine. As I was taking off the motherboard, I saw some black stuff on its back. There was some on the cpu metal area too.  I wiped some with Isopropyl alcohol and it came off. 

 

It doesn't feel any different to touch and doesn't come off with hands either. From my googling, it seems like flux but I am not sure.

[Bitz]

Yup! That's soldering flux. You can clean it off or leave it. 

[Windows7ge]

That's what I was thinking. Likely flux from manufacturing that didn't get cleaned off. It'll take some time but you could get it all off with paper towels, q-tips, & alcohol.

[boks]

10 minutes ago, Bitz said:

Yup! That's soldering flux. You can clean it off or leave it. 

 

1 minute ago, Windows7ge said:

That's what I was thinking. Likely flux from manufacturing that didn't get cleaned off. It'll take some time but you could get it all off with paper towels, q-tips, & alcohol.

Is there any harm in leaving it there, it doesn't bother me since its in the back.

[Bitz]

1 minute ago, boks said:

 

Is there any harm in leaving it there, it doesn't bother me since its in the back.

Nope, it has no effect to clean it or leave it. I'd personally clean it just because it would bother me knowing its there, lol.

[Windows7ge]

4 minutes ago, boks said:

Is there any harm in leaving it there, it doesn't bother me since its in the back.

Flux is not particularly conductive, it won't hurt anything leaving it there if removing it proves to be too much work.

[boks]

14 minutes ago, Bitz said:

Nope, it has no effect to clean it or leave it. I'd personally clean it just because it would bother me knowing its there, lol.

Ok thanks! I might clean it during maintenance someday. I just want to get this PC running for now.