Find out what is using the swap and do something to it. Or just get more RAM. Swap is after all a fallback for when you run out of RAM. Traditionally anyway. You could always add more swap if need be. Use dd to create a file, format it with a swap filesystem, and add it to the swap. By no means an efficient way to do it, but one option when other options are not immediately practical.
# dd if=/dev/zero of=fake.swap bs=8M count=10
# mkswap -v 1 fake.swap
# swapon -p -1 fake.swap
# swapon -s
About the only thing that was using swap on my desktop was icedtea-web. But I only have 1GB of RAM on this relic of a machine. So now I start my browser as follows.
$ JAVA_OPTS="-Xmx128m -Xms128m" padsp iceweasel