It always bothers me to see this happen, when it's so easy to prevent. Get the Hagen Quick filters, remove the inner cartridge, and they work great as pump screens. While they are made to fit Hagen powerheads, they can be adapted to fit Maxi-jets, or even Mag-drive pumps with a bit of ingenuity.
The larger ones are available at most LFS or on-line retailers. The smaller ones are harder to find, but one of my local LFS had a huge stock of them a while back, and I stocked up...VERY handy...