I downloaded Remastersys, and have made an ISO of my system. How do I remove stuff from it? It's too large to fit onto a CD, and I don't have a DVD-RW drive.

(mount the iso as a loopback device

copy the contents to some folder

then re-make the iso using mkisofs

(edit)

well
I think you need to first delete files or remove any unnecessary apps
and orphaned libs
also, clear your browsers cache/history and remove anything you dont need

I've made like 20 remastersys ubuntu's and debians, some manaully
some with remastersys, in the last week!

the way I did it it was I installed a minimal system via net-install (via netbootcd)
I unchecked everything during install, no desktop, no base system

I then rebooted after install and started apt-get'ing apps like lxde, gimp, etc
after adding just minimal stuff I kicked in remastersys backup
and kept adding stuff till I hit 670MB+kernel/initrd

my Canabix-LXDE iso is a remastersys make
I actually made 2
one is lxde using remastersys/ubuntu
http://community.canabix.org/smf/index.php?topic=71.0

and the other is my grml-magix manual remaster
http://community.canabix.org/smf/index.php?topic=70.0

check em out if you want

Okay, but could the problem be that remastersys included my home folder in the ISO and everything there, thereby inflating the ISO? I can't tell, because I don't know how to see everything that it put into the ISO.

You can see what you've put by mounting the iso, read my last post

the contents of the iso are a squashfs filesystem
mounting the iso isn't going to help
you can mount the squashfs too

but, did you do remastersys backup?
or did you do the distributable cd?

the backup includes everything in /home/user

if you dont want /home added, using remastersys gui
use the exclude files option

I selected remastersys backup--I think. I'll do "distributable CD" next time.