I traced a bitmap and after some tweaks I have what you can see in the image below (it’s a detail of the whole canvas). As you can see some small gaps exist in the middle of the PCB traces. All the image is a single path.
Is there a way I can fill/delete all these small gaps automatically, while not affecting the middle of those big circles?
A sample in SVG format can be found here.
Your file contains a sigle path, where the tiny holes and spurious white scratches are path borders just like all others.
If you select your huge path and call Path -> Break Apart, you will end up with many simpler closed paths, where the holes and scratches will also appear as paths.
At this point, if you call Path -> Combine you will get back to the beginning, where one path inside another will appear as a hole. Don’t to this.
Instead, with all the subpaths still selected, call Path -> Union. Voilá!
All overlapping holes and scratches will be merged with the bigger traces.
So the recipe is Break Apart and then Union.
Good luck cloning that PCB.