After official publication of our protocol in Bio-protocol (https://bio-protocol.org/e2919) we noted an error in the protocol.
The recipe for making the Sodium Chloride (NaCl), 8% solution (recipe #7) is off by a factor of 10 due to a numerical error: 4 grams, instead of 40 grams of NaCl. Accordingly, we have now corrected the recipe:

Sodium Chloride (NaCl), 8% solution

Dissolve 40 g NaCl (Sigma-Aldrich) in 500 ml distilled water, mix well
Filter sterilize using a 0.2 μm filter

References

Doyle, A. D. D. (2018). Fluorescent labeling of rat-tail collagen for 3D fluorescence imaging. Bio-protocol 8(13): e2919.