Packing the pottery

Text: an original contemporary personal account-style practice extract.

Before posting the handmade bowl, I put a smaller box inside a larger one and filled the gap between them with crumpled paper. The bowl was already wrapped inside the inner box. I shook the parcel gently to check whether anything moved, then wrote the address on the outer lid. My neighbour offered a padded envelope, but it was too shallow for the bowl. I kept the envelope for a different package. The finished parcel looked much larger than the object it protected.

From the extract, identify one material the writer used to fill the gap between the boxes.