Document the scene
Save one full outfit photograph and one detail of the fit. A simple note of the body model and costume makes a successful combination easier to recreate. If a seam was under tension, record that too rather than forcing the same fit next time.
Undress before you pack
Work slowly, supporting the fabric near the point that is moving. Check the body and costume for new marks. Keep accessories apart so a sharp edge cannot press into a glossy surface during storage.
Use only the cleaning method permitted for the costume. Let moisture dry in shade, then separate colours and avoid tight folds. Permanent wrapping is not a substitute for a suitable storage space.
Make the next session easy
Store pieces as an identifiable set without compressing them together. Keep the product listing or care instructions with your own notes. A little organisation makes it easier to spend the next session creating rather than searching.
If you discover a stain, pause and identify it. The Leather Lab separates surface marks from absorbed dye and records the precautions around chemical treatment.