The Bollegraaf Bottle Perforator is a system whereby plastic bottles (PET and HDPE) are perforated before the material enters the baler. After perforation, the material can be compacted efficiently into bales that are more homogenous, more compact and heavier. The perforated bottles free the bales of the risk of wires snapping as a result of rising pressure in air bubbles left in the compacted material. Now the air can escape via the holes punched into the bottles.

When unperforated bottles - often still with caps on them - are compacted, isolated air bubbles remain in the bale. When temperatures rise, for instance because bales are left in the sun, pressure increases and the tie wires on the bale can snap.