If u sink them in resin then u don’t have to worry about them being banged around and I think you’ll be better able to transfer heat through the resin than stagnant air. U could add a mounting fixture to the potting.
Could pot them in a low temp theroform resin and extract them for recycling later.
https://www.plastikcity.co.uk/useful-stuff/material-melt-mould-temperatures