When fixing my Marzocchi 48 I developed this wooden clamps to avoid damage on forks and a half PVC bowl to clean internal parts.
Marzocchi closed chamber fork has a special 8 sided cap tool seen in this video too (1:40). It was made filing a regular 6 sided nut.
The cap tool is the same used to Kayaba and Showa forks.
There english subtitles in this video.