How can i remove cement render from the window glass?

Question

Had th eplace rendered and have cement all over the windows
tried bi carb with vinegar but didnt work

Answer 1

When you say cement do you mean household cement or concrete?
If it's concrete use just vinegar and not the bi-carb try to attach a wet papertowel with vinegar.
If it's household cement "GooGone"
This stuff will remove that spray foam insulation
from the spray tube and hole so that you can just use part of the can of spray foam.
See product below
http://www.googone.com/products_gg.aspx

Answer 2

Stanley knife blade - but be very careful!! Those things you can put blades into are much safer. Think they are sold in the decorating section.

Answer 3

if you try to rub it off you will scratch the glass...use a razor blade to try and get under it...