How do I remove white spots from an oil painting? Are these moulds, and how to prevent in future? ?

Could this be caused by warmth and humidity in Singapore where I live? I also have some light brown spots on my watercolor paintings. Would appreciate any advice on how to remove these spots safely, and how to prevent reoccurrence. ThanksHow do I remove white spots from an oil painting? Are these moulds, and how to prevent in future? ?
The oil painting surface should be tough enough to clean with mild soapy water and soft cloth. Rinse with clear water, dry and seal with Damar varnish. Check the back side of the canvas too. If the spots are there in the same places as on the front, it would be more difficult to eliminate the mold and protect the painting. I don't know how you would do that.


The watercolor is a different story. There is really no way to fix those unless you are a trained conservator. Brown spots sound more like non-archival material (not acid free) was used to frame the paintings.


Prevention would require framing with acid fee mats and backing board and under glass with acid free paper seal over the back. If the pieces are not framed, seal them in archival plastic sleeves and store flat.


Good luck!