Anyone who welds should read this....

[Louwai]

I agree that it's good to display & distribute this type of info, but people who are properly trained would not do it in the first place.

That comment relates to 2 things.
#1 People who do it without training
#2 People who have been "trained" by less than suitable trainers, & THINK they are doing the right thing.

I'm a boilermaker. I finished my apprenticeship over 25yrs ago. One of the major things we were taught was,
DO NOT LET ANYTHING INTO THE WELD.
The reason for this was not fumes or safety, it was to stop porosity in the weld.
Those who are dilligent & want a perfect weld will never "just burn it out".
I spent several yrs repairing damaged Aluminimum & Steel fuel tankers. (Semi-trailers) as well as diesel tanks for locomotives.
The cleaning sequence was;
#1 Clean / wipe / flush with Shelite (to remove fuel residue & Shelite will evaporate totally)
#2 Steam Clean for 2hrs, (to totally remove fuel residue & shelite residue)
#3 Grind (to remove rust, scale etc)

Therefore, if the components are cleaned correctly, the scenario above should never happen.

But of course, we all know that we don't live in a perfect world.
The sad part is, a lot of people won't even head such a warning & do it anyway......