The Natural History Museum's famous Whale Hall is undergoing a through clean to remove years of dust build-up.
The central London gallery houses five whale skeletons, such as a 116-year-old blue whale skeleton, and 21 models, including a 27m blue whale.
Equipped with specialist vacuum cleaners and hog hair bristle brushes, museum conservators will work their way round the exhibits on scaffolding.
The hall has been closed since 30 April and is due to reopen in July.
The clean-up - expected to take the team 120 hours is the first since 1995.
Any cracks and gaps in the exhibits will be filled with conservation grade and fully reversible synthetic resin.
A museum spokesman said the work was essential to safeguard "the museum collections for the enjoyment and education of future generations of visitors".
The blue whale model was built in situ during 20 months and was unveiled in 1938.
The model is the biggest single object in the museum, three metres bigger than the Diplodocus in the Central Hall.