I want to experiment shielding "things" from very low frequencies.
What metal or alloy is the best?

I would recommend very conductive metals that are very well grounded...

Are you talking about electrical or noise frequency? Big difference!

For your first test, may I suggest Aluminium foil. You would be surprised at what that will protect.

Of course you could always use nothing and when a failure occurs, simply move the failing device 90 degrees out of phase with the signal.

This is more of an electronics question than an electrical question.

Since the OP hasn't answered, it could be transmitted low frequency noises rather than electrical issue.

Maybe the OP can't respond because of the low freq interference )

Since the OP hasn't answered, it could be transmitted low frequency noises rather than electrical issue.

Yes, you're right. They are a form of transmitted low frequency noises or interference. Actually it probably includes higher frequencies as well. I'm looking into
Isolating the problem and low frequencies is the starting point.
It might clarify if I said my body is what I want to shield or insulate from said radiations or frequencies. I'm beginning to study charts etc of the full EM range
And I discovered the certain ferrous alloys work well in certain ranges...
Thank you very much for your response and interest

EM radiation is not the same as low frequency noise. What is your concern and is this EM or noise?