Usually older pianos are found covered by dust on soundboard and plate. I opened the lid to exam how dusty this Chickering was only to find hidden cash and jewelries under lid on plate. The owner complete forgot they were there. We laughed hard. The soundboard cleaning tool can be found online like here. The design is to have something going through the strings to clean soundboard surface. A vacuum is handy here to suck in dust on cleaning tool.
The tuning pin area can be cleaned by soft long brushes with help of vacuum cleaner. The piano is more pleasant to tune after it/she/he is cleaned. If the tuning pins are loose and won't hold the strings at pitch, thin superglue can be added where pins go into pinblock. This piano drank four 0.18oz/5g bottles of glue applied twice back to back. Now it/she/he should hold in tune for 4 to 5 years. The whole cleaning and gluing took about 45 minutes but well worth it. Talk to customers before the process since it is charged by the hour.