permanized mengel dresser

Seeing pictures of those blotchy spots may help others who are familiar with this brand tell you more. You need to take good pictures and upload them to this site.

 

Most likely. Much furniture from this era uses toners to give a uniform look to the finish. It is nearly impossible to sand them uniformly and you will get blotchyness as a result. You can try to sand some more but be aware that these are usually veneer and you run the risk of sanding through the veneer. Another option would be to paint.

 

Or, just "skip" it.