I have cleaned several waterlogged magnetic tapes at home with excellent
results. You have to incrementally unspool the tape while cleaning it
in a bathtub with soap and water, then rinse it with purified water
and hydrogen peroxide, and finally bake it. Yes, bake it. It's what the
This is a long and tedious process, but if you have the time to do it,
you'll save a lot of money. If you have many tapes to clean in a short
time, try to gather some friends and relatives to help you.
When you wash the tape in your bathtub, don't unspool the whole length at
one time, or it will get hopelessly tangled. Just loosen the tape from the
cartridge so that two or three feet are hanging out. Clean that length
of tape unidirectionally (opposite the winding direction) with a soft,
clean, soapy wet cloth, then wind it into the case and repeat for the
next two or three feet. I should also mention that some brands of soap
contain solvents that can damage your tape, but I have had no trouble
using a mild dish soap such as original Palmolive.
Once you've washed the entire tape in this manner, transfer it to a large
basin of purified water (the kind you buy in 5-gallon bottles at a water
store) and rewind it, rinsing the tape of all soap residue. Magnetic
tape has a slick coating with low surface resistance, so the rinsing
isn't very difficult.
Now wind through the tape a third time, swabbing the surface with hydrogen
peroxide to remove any remaining contaminants. The greatest danger to
the integrity of your tape is posed by small particulate matter, which
can shred your tape as it spools through a machine at high velocity. The
goal of all this cleaning is to remove the particles without scratching
the tape. A few scratches are inevitable, but with analog media you will
suffer only a slight degradation of image quality as long as you proceed
carefully. With digital media you may lose some frames, but most of the
content should come through intact due to the error-correction codes
built into the recording process.
The final step, baking, calls for less labor but more precision. The
most important thing about baking is to maintain a constant temperature
over the entire tape, or else it will suffer warping and other ill
effects. This means that you can't rely on ordinary gas or electric
ovens, which are susceptible to shifting cold spots and hot spots. A hair
dryer isn't a good solution either. If your kitchen is equipped with a
convection oven, which maintains a uniform temperature by circulating
air through the heating space, you can use that. Otherwise, buy a good
food dehydrator such as the American Harvest model shown about one-third
of the way down the following page.
Tangible Technology: If I Knew You Were Coming I?d Have Baked A Tape!
That page also includes instructions on baking your tape. The author
recommends baking for two hours at 130 degrees Fahrenheit, but I baked
my own tapes at 120 degrees for six hours. See the following page for
another, very similar set of instructions.
Radio College: Baking Old Tapes is a Recipe for Success
When the baking is done, your tape will have come loose around the
cartridge spools. You should manually wind and rewind the tape to
remedy this. Also, don't forget to thoroughly clean the tape heads of
your machine with a cleaning cartridge. My final tip is that you should
transfer the tape contents to disk or to another tape immediately, and
I mean the very first time you play a restored tape. The washing and
baking process can weaken tape to the point where it won't survive more
than one or two trips through the machine.
It has been a pleasure to address this question on your behalf.