In the armed forces they were and still are used for field dressings or now sometimes called surgical dressings because of their absorbency.
On the womens unit in the hospital they are called maternity pads.
They were created and used by the military before women found another use for them.
Perhaps he was a Medic in the forces and got used to packing them "just in case".
He could have also found another use for them.
Like...mattresses for mice.
A druggie wouldn't be that meticulous.
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