Efficient washing technique can save you time, save plastic, water and provide reliable labware for your experiments. This set up is to wash plastic and glass to remove ions for moderate to high surface purity in a soil chemistry laboratory.
1. Know the limits of contamination for your work and the best way to remove contaminants.
a. There are two ways to remove tarry organic residues: you may scrub and rinse with a lot of solvents, or you may put the item in a muffle furnace (after removing the bulk of it). If you combust a full load of dirty glassware, this may use less resources than all the solvents needed to clean them.
b. If a bottle only had inert salts in it and not any compounds that you are studying, give it three quick rinses at the sink and put it up on a drying rack instead of leaving it on a counter to get a full acid soak with contaminated items
2. Know likely contamination sources to avoid.
3. Wash when practical: if any single disposable item needs extra attention due to gummy residues or scrubbing, chuck it.
4. When pre-washing keep heavy solids (e.g. sand) from going down the drain. Pre-rinse jars in a basin to catch the heavy solids, pour off the water and drain off most of the liquid. The sand may be thrown in the trash if not too heavy.
Set up a washing area that is efficient to use. Set up five basins: Soap and water; tap water rinse; two, five or ten percent hydrochloric acid rinse; two deionized water rinse basins. (See five basin set-up). This is always set up in the lab.
5. Wash multiple items in racks of 40-60.
6. Retain and drain tubes using lengths of plastic rain gutter screen.
7. Dunk items in successive basins to wash, (a.k.a Deep Fat Frying)
8. Soak in acid for several minutes to hours, depending on purity requirements. Use the minimum necessary acid concentration, (2, 5, or 10% HCl).
9. Dry items on their sides after shaking off excess water.
10. Keep multiple disposables organized in racks or baskets and keep them separated so they do not need sorting later.
11. Baskets or basins full of small items will need drying in an oven less than 90 degrees C.