Why is it permissible to use a wet bottle when first obtaining your kmno4 solution?

For the answer to the question above, well presumably because the exact concentration of the composition KMnO4 solution doesn't matter. If the concentration of the KMnO4 solution is important (usually in titrations etc.) then it is not allowed to use a wet bottle. The water in the bottle will dilute the KMnO4 solution and change the concentration of the said compound.