cleaning up a computer to sell

i take dusty ones outside and stick an airhose to em, dust em out good! ; )
mid age boxes using ps2 keyboard and mouse are most common. Older ones usually need a Ps1(larger round plug) keyboard and a serial db9 pin plug mouse (just a couple things needed occasionally for testing/checking older ones out. Most any 15 pin monitor will work on most any IBM compatible computer. These few things will get you through about 90% of computers you'll likely run across