Possible Aluminum contamination in mild steel weld

I have mild steel coated with aluminum paint that I need to weld.
I one instance it is an old construction that needs to be repaired.
It has a coat of aluminum paint over painted with normal gloss paint. I intend to do a reasonable paint removing job before I fix the cracked welds and add some more braces.
I also have reasonably clean steel coated with a light layer of aluminum paint. The owner had it cleaned and painted to prevent rust formation during storage. The project was interrupted for a while.
How thorough do I have to clean the aluminum paint. It seems a little bit of aluminum 'contamination' in a steel welds do not affect the steel welds.
I intend to use 6013 electrodes or would you guys recommend 6010 or 6011 or possible other electrodes for the task.
Gerhard van den Berg
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I usually remove paint by burning with a cutting torch. Using a very robust torch setting, travel slowly along the weld area, then buff with a wire brush. If necessary, repeat.
If you experience bubbling in the paint adjacent to the weld during repair, buff before it cools to leave the smoothest possible surface for repainting.
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