Today I have been to a Yamaha U1 at a school. The first 22 bass strings had lost all tone and sustain. I thought that the bass bridge must have come unglued, but on further inspection a fizzy drink has spilled through the top hinge and down onto the bass strings. There is tell tale evidence on the celeste rail, hammers, soundboard and pedal board.

Does anyone know if the sugar will crystalise and eventually fall off, or is it a new set of bass strings.

Thanks again,

New strings.

New bass strings, new dampers perhaps, new hammers perhaps, to do it correctly.

Thanks for the prompt and unequivocal replies.

What everyone else said.... and beat the student who did it.

After a frat. party at Bowdin College in the early 70s I discovered that a rather nice small grand had suffered an angel food cake and Coke attack. I told them to write it off. After at least one more tuner told them the same thing, they did.

Sugar and water is bad for pianos!

All good responses -- Including beating the student(s) responsible.

For a contrarian position, if I were in an experimental mood, I'd unhitch the bass strings and give them an alcohol bath and scrubbing. Water with a surfactant could also be attempted but there would need to be a way to completely dry the strings. (Heat gun?? Hair dryer??)

Let the offending student suck them dry...

Keith,

Given the unanimous sentiments here, I wouldn't have written this of my own, but as you've already posted a contrarian position: from a chemist's perspective, I would suggest a two-stage cleaning process:
1) Warm water with a little surfactant, to dissolve the sugary spill, preferably followed by a rinse in clean, warm water,
2) Alcohol (or even acetone) to remove the water and act as a quick-drying solvent, followed by judicious use of a hair drier (someone posted about this recently) or personally I'd consider a 10 minute stint in an oven at about 85-90°C (190°F), but I'm not sure whether this would affect the work hardening of the steel and/or copper wire.

Plus the taste of the drink get awful when mixed with bass strings

Removing the bass strings and cleaning them is virtually the same amount of work as replacing the set minus the cost of bass strings.

Bathing the strings, drying them etc etc is probably the longer process. There is no guarantee all of the contamination will be removed.

Replacement bass strings guarantee success of tonal return.

Soon thereafter the top hinge will have to be removed and cleaned too.

If the bass strings were simply unhitched, there would conceivably be less time.

Absolutely right about the top hinge.