How can I delete email addresses from mail forwarded to me?

My friends and I exchange lots of forwarded material, but sometimes when I receive it, there is a whole list of other people who have also received this e-mail. Sometimes I want to forward the e-mail to someone else, but I don't want the whole long list...

Most times you really have to wade through a lot of forwarded addresses to finally get to the message of the email. I have highlighted all the addresses and right clicked "delete" but most times delete is not offered as an option.

Some forwards have addresses for more that 20 people. I would rather not include them when I forward an e-mail. On comcast all I had to do was highlight them and hit delete. This does not work with yahoo. What can I do?

I've tried many online suggestions but none work. I am trying to delete invalid email contact addresses from appearing when I open a new mail. I only want to see the current address. I use Windows 7 and Yahoo mail.

when mail is forwarded to you and you want to forward it but do not want the previous addresses to show

SOMETIMES I get e-mail with many addresses included . I would like to forward these but don't want to include all the addresses

I get lots of forwarded e-mails that I would like to forward on to others but don't want to send the e-mail addresses shown in the original.

I want to remove them to reduce the size of the email and not pass on other people's addresses. Thanks to anyone who helps with this. I can't remove them on yahoo mail like I did on the old one that I was using.

Okay, so I have my emails from my old account that I don't use anymore sent to my mail app on my laptop. I actually need to up it now for my school email, but I can't figure out how to delete my old email address and set up my new one? If anyone can...