Cancelling certain commits

Hi,

If I'm not happy with the changes I made in certain commits during development, how do I cancel those commits and remove them from git records most cleanly?

For example if I did commits 1 to 10, and want to get rid of commit 3 and 7, such that, the other commits are irrelevant to changes made in 3 and 7, but may involve changes in the same file as 3 and 7 changed, how do I handle it?

Furthermore, how would I handle it if there was a commit 4, that depended partially on commit 3? (For example if it uses a type that was changed in commit 3?) Would I hand-edit commit 4 to fix it?

Many thanks, Bahadir