What are Frank's plans for spring cleaning of his residence in Moscow that appear in Chapter 26?

Penelope Fitzgerald reveals in Chapter 26 that Frank has plans to open 22 Lipka, as it is time to conduct the spring-cleaning of his residence. She also lets it be known he has been putting it off until his children come back because he is aware they will be disappointed if they miss it. On Saturday, Frank plans to travel to their dacha to fetch them.