This post describes how cached SVN credentials can be removed. Credentials are stored in SVN auth disk area. They have to be removed in order to remove cached SVN credentials.
$ ls ~/.subversion/auth/svn.simple/ 5671adf2865e267db74f09ba6f872c28 3893ed123b39500bca8a0b382839198e 5c3c22968347b390f349ff340196ed39
These files hold the credentials for a certain domain. If you take a look inside a file the domain is listed under
svn:realmstring key. Delete the corresponding cache file to remove the credential for the relevant domain.
K 8 username V 3 joe K 8 password V 4 blah K 15 svn:realmstring V 45 <https://svn.domain.com:443> END