When ever I use glassware or plasticware in the lab to test water parameters I use soap and water to wash and rinse it, I also scrub the surface with a pipecleaner, sponge, towel, etc. This, I believe, is the best, inexpensive, way to keep organics from building up on glass and even on plastic if done before the water dries in the container. When you do calcium testing there can be a buildup of "stuff" on the glass or plastic, which can usually be removed by a good dose of vinegar and then wash with soap and water. If you don't see a buildup you don't really have to use the vinegar.