How does Bud make a hole to see outside?

Bud used a jack knife to make a hole big enough that he could see outside.

I took out my jack knife and tried scraping the newspaper with it. The paper peeled away in little curly yellow strips like that stuff rich people throw on New Year's Eve. I finally got a hole big enough to look out and mashed my eye up against the glass. I could see the back of the Amos house real clean.