From a strict Jain cooking point of view, it is not the ideal practice.

• If a utensil has been used for non-Jain food, then washing it well is necessary, but the best practice is to keep separate utensils only for Jain cooking.
• Putting foil inside does not fully make it pure in the strict sense, because the base utensil is still the same non-Jain utensil.
• If there is no direct contact with leftover non-Jain matter and the utensil is thoroughly cleaned, some people may use it as a practical compromise in difficult situations, but it is not the most proper Jain method.

So, the safest Jain rule is:

Use dedicated, separate utensils for Jain cooking.

If you want, I can also give a simple Jain kitchen purity rule list.