clearing data from partitions

[john gennard <joney@clara.co.uk>]

I have a large hard drive divided into many partitions so that I
can try new distros. Two large partitions hold Sarge and Unstable.

Grub picks up everything and I have a quite large menu.lst file.
I want to find the safest way to 'clear' the contents of partitions
that I no longer need.

I know I can use fdisk or cfdisk to delete each partition, 
immediately recreate and then format with say ext3.
Is there any simple way to accomplish what I want?

John.

P.S. I've tried deletions in the menu.lst file, but the next time
try another distro, grub picks up everything again.