Is this a sign of venting?

[cook]

This board is for the controller on a house water heater.

In the center of the picture, notice the yellowish color in the vent grooves on the top of the capacitor. That color is not a reflection from the yellow wire near the capacitor. The color is actually in the groove. The same color is on the cap on the right side of the picture too, but it does not show up as well. I don't think I have ever seen something like this before...

Generally speaking, is that a sign of venting?

[stj]

it looks like something got wiped across them.
electrolyte is usually darker on colour - and the metal pushes up before it comes out.
that said, i wont cost much to change them anyway.

[cook]

Yes, that makes sense. Something may have been wiped across them. I had not thought of that. I will replace them since they are easy to get to, and as noted, they won't cost much. ---- Thanks

[momaka]

Replace only if they are very old and/or cap brands/series that have problems. Otherwise, there's just no need, even if they don't cost much. I don't replace caps every time I open a device for inspection if I see good caps that don't have many years of use on them.

As for the yellow stuff - I can't quite tell from that picture, but does the PCB appear to have a thin coating of this as well? If so, that might be some kind of a sealant or lacquer/varnish. And if not, it might be some kind of a QC marker put on certain components when the PCB was checked in the assembly for QC issues.

[PeteS in CA]

Looks like an inspector's mark, possibly signifying that the polarity is OK.