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

Gerhard van den Berg