I am making a full sheet cake for this weekend for a graduation and I can't find a full sheet cake box anywhere. It was a last minute order so I didn't have time to order any or anything like that. Anyways, I have the top of a full sheet cake box I just don't have the bottom to go with it (had to use it for a cake last weekend). So my question is do you think it would be ok to reinforce the top of the box and use that as the box and then just use like the Glad press in seal plastic wrap to cover the top? Do you think that the cake will stay fresh that way? She is picking the cake up Friday morning and the graduation isn't until Saturday. Thanks for your help.

Putting a cake in a box does not keep it fresh :)  It only protects the cake from getting any dust, etc on it.  What you thought of doing is fine.  If the customer says anything, explain her last minute order prevented you from having a proper box.

Cool, Thanks!