I can't imagine they are making their product on an order-by-order basis. Nor would they be buying supplies for their product that way, and selling back supplies is not a frictionless process. Of course there is a stockpile.
Unless they're adding something to the plastic, or coating it in something, they could absolutely just ship it back as smaller than usual nurdles, or make use of it for something else in their manufacturing process, like making bottles or caps.
In any case, do you really think they have a two year supply of this stuff? That'd be crazy.
Toothpaste and facewash?
I find it very plausible that they have a two-year supply of particular products, that can easily happen if demand does not meet expectations, or if they planned limited campaigns of particular products.
This isn't the 1920s. Most major companies run on much leaner inventory, and it's not uncommon to turn over your entire warehouse several times a month.