Does oversize letter mail and light packet go through a flattening machine? How can I prevent this

[smchacko314]

I've read some posts mentioning letter mail going through machines to test thickness. Does this apply to light packet as well?

Is there anything I can mark my letter mail or light packet with so that it isn't put through a machine? I have sent some gaming cards and plan on sending some video games and condition is important so I don't want them to get damaged.

[toby_le_pue]

It don't go through a flattening machine,

Oversize lettermail does have to go through a 2 centimeter slot

and be weighed.

You can find the rates for the different weights on the CP site.