Ideas for window rubber gasket

[vinny186]

My casement Windows have been leaking so I got a roll of foam filled rubber gasket but I can't close them due to the extra thickness. My old rubber seal had foam but it wasn't all foam thru the center.
Any ideas on how I could reduce the thickness?

 

[Snoonyb]

I wish you had asked, before you purchased, so I could have referred you as follows; https://www.grainger.com/product/2E..._on_Your_Search-_-IDPPLARECS&cm_vc=IDPPLARECS

 

[vinny186]

Thanks for the link. I can't return the rubber seals so I have to make them work somehow.

 

[Snoonyb]

Generally, you'll probably need to become a surgeon with a razor blade.

 

[vinny186]

I tried drilling out the center of the foam but that went nowhere so as suggested I've pulled out the razor blade.