I can agree that dry rods make a big difference, but no matter how dry old rods are fresh new rods will always be better

I welded with satincraft and artcraft rods for ages, I baught some new cheapies and some new funky striped WIA rods recently, and opened a box of low hydrogen rods I snatched on a deal some time ago.
All these rods are very different to work with and the slag looks different too...& yep the low hydrogen rods produce a slag that is softer thicker and does not seem come away as cleanly especilay at the edges.

A little while ago I had 5 different packets of rods open at the same time & I was struck by how different they all were to work with.

I have worn predominatly cotton, I certainly will not wear synthetics when welding.

Even cotton will burn given a chance but it wont turn into an incendiary gloop that heat fuses into your skin.

big brother ( the pro metalworker in the family) wont wear overalls and always welds with his shirt untucked. I seem to think he had some experiences with slag in the grundies as an apprentice.

A good flat weld with any of the easy welding rods.....the slag should pretty well curl up and fall off as it cools.

Oh keeping you chipping hammer sharp helps too
cheers