Junk Mail and Blocking

I am receiving quite a large amounts of Junk mail coming through to my email address. I always transfer these emails to the Junk file and then attempt to Block them but I am finding more and more that they are not blockable and I end up just deleting them.

When I try and block most of the junk mails that are coming through now I get a box come up saying the senders address isn't valid and wont allow it to be blocked. These junk emails have some extra text after the email address which is distorting the address and hence it's not showing it as a valid address. e.g. An address ending .com may have ...? additional text showing immediately after it so appearing .com...? Is there any way of getting around this problem?