Talk to your suppliers about not providing single-use plastic packaging
It's always worth asking your suppliers if they might have the capacity to supply better options, even if only to bring their attention to this problem and to encourage them to think about it for next time.
Here is a template supplier letter you can edit and use.
Another good way to bring attention to this matter and to encourage suppliers to review and avoid excessive use of plastic packaging, is to return any back-of-house plastic packaging to the supplier with their equipment. This includes (but is not limited to) staging, sound/video/lighting equipment, on-site facilities (ie. toilets) or crowd controls (ie. fencing).