@ptss
I just don't believe you can slap a little bit of some 'magic' material to tackle emissions. EMC compliance (includes RFI/EMI emissions) is big business in Europe and companies spend millions to ensure their products meet the requirements at all stages of product development. At the design stage you account for emissions and you control them using various design techniques. Then there are several stages of EMC testing before a product is released to production.
If you believe you have emissions issues you need to measure it and then decide what to do about it. I am assuming that you mean emissions when you say stray digital noise. What do you think is the root of it, where is it coming from?