In order to carry out any work in the laboratory correctly, it is necessary to always keep the material and the working table clean, especially if we are talking about the chemistry pipettes. The material must be clean and dry before beginning the experiment.
The cleaning of the material should be carried out immediately after each operation, since it is much easier and the nature of the residue it contains is well known. In the case of chemistry pipettes, it is necessary to remember the materials that were measured for subsequent cleaning.
To clean an object, first remove the residue (that is thrown away in the appropriate container) with a spatula or rod in the case of large instruments and then clean it with the appropriate solvent, especially on smaller instruments such as pipettes chemistry.
Soapy water is one of the best cleaning methods. Acids, bases or organic solvents are occasionally used to remove all difficult residues. It all depends on what you used on your chemistry pipettes.
The final washing operation consists of rinsing all the material with distilled water. The clean material is dried on an appropriate inclined or vertical support, either by placing the material upside down or by using a drying stove. In the latter case, the material must be introduced into the stove without plugs or keys.
It is important that you remember never to leave your chemistry pipettes in the stove.
There are other methods to wash the material that involve the use of more aggressive agents (acids, bases, royal water, chromic mixture, alcoholic potash, etc.). If you have an intractable residue consult with experts.