Labeling considered important
You are in possession of: two identical bottles containing the same volume of colorless liquid. Bottle 1, labeled "A" contains liquid A; bottle 2, labeled "B" contains liquid B [ie the only distinguishing marks are the labels].
And you are not in possession of: a photographic memory that remembers little details like the spatial ordering of the bottles and labels
And you want to: rewrite the labels to make them more legible
Do not: rip off both labels at once, wad them up and throw them into the trash
Because you will: not have any clue which bottle contains which liquid. And you will have to remake said liquids, which may or may not be a huge pain in the posterior. Especially if you have, 10 minutes previously, spilled most of your supply of one of the necessary components, all over your lab bench.
This concludes today's lesson in "Short Non-Protocols in Molecular Biology". Thank you for your attention. You may now return to your regularly-scheduled cloning.