What is the ruling on drops of tea, soft drinks, broth, and all types of foods and beverages if they get on clothes? And must they be washed, or are they pure and considered to be from the second category of water, which is water altered by pure substances?

The things mentioned in the question are pure and do not necessitate washing if they come into contact with clothes, because the default state of things is purity, and whatever has no evidence of impurity remains pure.

These substances, despite their purity, are not permissible for ritual purification, because the designation 'water' ceases to apply to them due to what has mixed with them and predominated over them.

Ibn Qudamah mentioned that al-ma’ al-mudaf (added water) does not achieve purification. This is of several types: water extracted from pure substances, water mixed with a pure substance such that its name changes, and water in which a pure substance has been cooked and thereby altered. All these types are impermissible for performing wudu' or ghusl.