The process is much the same as that for removing mold and mildew from video tapes, but probably with a better chance of success. If the tea contained milk and/or sugar, it is important to remove as much of these contaminants as possible. If the tea spilled onto a table on which a tape was lying and penetrated the interior of the cassette, it will have to be dismantled to clean properly.

You should very carefully clean the tape with a soft cloth (e.g., a lens cloth) and a solution of mild soapy water (a couple of drops of dish detergent in litre of water), followed by a thorough water rinse. Do not scrub the tape, as you may damage the magnetic coating. If this layer is rubbed off, the content is also rubbed off.

This is a finicky operation, because you either have to draw the tape out of the housing foot by foot or disassemble the cassette, remove the tape, clean the tape and the interior of the cassette, and then reassemble the cartridge. It is difficult to unroll and then neatly roll up the tape afterwards, but will be necessary if any liquids penetrated the cassette interior.

If you decide to clean the tape by drawing it out of the cassette, you will need to remove the guard or use a piece of adhesive tape to hold it out of the way. The tape is locked when the cartridge is removed from the VCR, but can be unlocked by pressing a recessed button near the centre on the bottom of the cassette. The cassette can be dismantled by removing the screws holding it together and carefully separating the two halfs. Keep track of where each part goes and how they are attached.

I do not recommend using chemical cleaners on the tape itself, because of the potential for damage if the wrong chemical is used. Some people like alcohol-based cleaners, but I prefer to avoid them when cleaning media.

I normally handle media of any kind - optical, magnetic, or vinyl - by replacing them in their case or sleeve immediately after use and putting them back where they belong. I don't like to leave anything lying around, especially outside of a storage case or sleeve, because it is an invitation to spills, scratches, and other accidents.