A useful tip from Eric Pentecost:
Keeping Meccano separated and protected in whatever storage boxes or drawers are used can be done in many ways. One easy and cheap solution for partitioning piles of small Meccano items is to use cardboard trays.
One supplier of such trays is UKGE Ltd who actually produce these as museum specimen trays. The trays they supply are black or white in a number of different sizes, with even the largest (5" by 3.5") only costing 20p each (as at March 2021).
No glue is required just a little bending as they are supplied flat so easy to store.