Welding Tips and Tricks

Hi guys hope this finds you all well.
A friend has asked me to fix a staino panel for him. Its part of a large structure and appears to have gotten ferritc sparks on the panel and few weeks after install. The supplier is saying that it wasnt them so no recourse there without a long to and fro.
And I am confident my mate doesnt use angle grinders in the house or at all, he is more of a Chef.
So the issue is how do I get rid of it permenantly. I do staino and do it ok but Ive never had to fix anything staino. So would like to hear from those that have.
I am confident that pickling will get rid of it but for how long? It will come back? Is there any actual fixes? It is in the kitchen so I cant rinse off too much around the appliances.
Thanks in advance.

If the damage is indeed due to ferrous metal sparks then there is embedded material contaminating that panel. “Pickling” alone won’t resolve the issue. You need to remove the contaminants, then passionate the panel (possibly) and you can buff it up afterwards for a better appearance.

Not sure of the finish or thickness, but I would hit it with a burnisher until it was gone, if the finish has scratches in it, you can use a sulfur block to blend them back in. May even want to buff it with some automotive wax or a food safe wax afterwards in case you miss some or it's too deep to get all of it without pitting (shouldn't pit if it's just a grinder but never know), to help keep it from rusting. My 2 cents anyways, good luck!