Evaporust in canteen left yellow stains on weld

[Boone68]

Hey all, I recently picked up a stainless steel horizontal weld canteen and went through some processes of cleaning the inside. Being my first time doing it I wanted to be thorough, so I opted to soak the inside with some evaporust for 24 hours. When I emptied it and rinsed it out, I noticed that a bright yellow buildup had formed all along the weld inside. After shaking it with BBs multiple times, washing it with boiling water and baking soda, and going at the inside weld with a toothbrush and lots of Q tips I was able to remove a lot of it but not all. Anybody experience this before or have any tips?

[Blacksmith]

Are you planning to drink out of it?

 

If so, don’t.

 

If not, just put the cap on.

 

 

[Airborne-Hunter]

Just a guess, but that yellow looks like sulfur. Evaporust contains sulfur. Residual evaporust could have accumulated in the gap, evaporated and left behind a bright yellow sulfur. Evaporust is supposed to be safe on lead. That seam is lead soldered. In theory the lead shouldn't have been bothered by the evaporust, but there are yellow lead precipitates, which are all toxic in my book. I would not use this, but likewise I would not put hard cleaners inside and use a canteen either. If anything, Dawn soap is enough.  ABN