Send only filled form fields

I've added extra form fields and I'm using $message to send form field info to my mail.

How can I exclude empty form fields from received form mail?

I already have some obligatory fields but these other fields must stay the way they are (optional to fill). I just don't want to receive them in my mail if the user leave them empty.

Can anybody help?

Thank you!

[Scott]

Could you post some of your code, specifically where you are including your additional fields into $message..