Bleach in a solution of 1 part bleach to 30 parts water is more than enough to kill any little nasties depending on how long you leave it on a surface...it's also the cheapest though you do have to be sure to rinse thoroughly (granted, your solution, if mixed properly, shound not have a strong bleach smell at all)! The safest and probably next best in antimicrobial activity would be chlorhexadine (Nolvesan)...you dilute it as well so a jug lasts for quite some time. We use chlorhex quite a bit in our clinic as it disinfects almost as well as bleach AND you can use it on the skin to flush wounds hence making it a safe alternative!