Hello, I have done a few evaporation tests but am not convinced the Petri dishes I have used were clean enough for the results to be valid. I say this because after cleaning with soap and hot water, there are still thin stains in a certain light. How would one clean their glass sufficiently enough so when doing an evap test, the surface is clean as can be?

Thank you

Wash it with distilled vinegar maybe, so at least you don't get limescale stains from your (presumably tap) water?

Okay, once I wash it with this distilled vinegar, is patting it down with some paper towel advisable, or instead letting it evaporate? Also, yes, high quality tap water.

I always use IPA, then water and then paper towel.

Fantastic, will get some tomorrow

This worked perfectly much appreciated