Resetting Mark In and Out
For those who have already marked in and out their master clips and wish to reset them back to their original way you can do this by:
1) On the browser, select the clip/s you wish to reset back to their original default mark in/out.
2) Locate the sort tabs that says In and Out. It's located where the Name, Duration, Media Start, Media End is. Right click inside the In column (ie 00:00:00:00) and a small menu will appear. Select Clear In. This will reset the Mark In. You can select multiple master clips and remove all the Mark In's at once.
3) You can also remove the Mark Out's on the Out column using the same step. In this case it will be Clear Out.
Final Cut Pro 7, Mac OS X (10.7.3)