This lovely violin had an old crack that was beginning to reopen and fill with grime, as seen to the left. Always more of a challenge when the crack ends blind in the middle of the top!
Below left, apologies for the blurry photo, one can see the caramelized sludge when the crack is flexed for cleaning. Below right is a photo after the crack has been cleaned, one has to be very careful to leave the wood intact while cleaning for a good glue joint.
The middle two photos below show the clamping during glue up and cleating processes. Cleating reinforces the crack and hopefully prevents another reopening.