Marty, That is is great question. You asked "How old can peanuts be for boiling?"
The answer is that it depends. It depends on their moisture content, and how they were stored.
If they are green peanuts, fresh dug, and full of moisture then they must be refrigerated, boiled, roasted, or frozen immediately. Green peanuts can be frozen, for at least 6 months.
Dried peanuts stored at room temperature may still be good when boiled at least one year after harvest.
BPW
Feb 16, 2018
Freezing peanuts by: Rich's peanuts
I noticed if you freeze peanuts after draining them they loose they're texture. Anyone else notice that?