hey there, go to call mode and click on top middle, takes to call log you can delete by selecting one or touch select all, (it will highlight blue) click on the buttom left X that should do it.
And if you are running 5.0 go into the messages folder,menu button,view folder, then look in call log and missed calls. Delete them there as well. 5.0 won't delete them all from one area like 4.7 did. Yes another glitch!