-The other way is to call @command{gnulib-tool} again, with the changed
-command-line options. Note that this doesn't let you remove modules,
-because as you just learned, the list of modules is always cumulated.
-Also this way is often impractical, because you don't remember the way
-you invoked @code{gnulib-tool} last time.
+@item
+@code{gnulib-tool} remembers which modules were used last time. If you
+want to rely on @code{gnulib-tool}'s own memory of the last used
+options and module names, you can use the commands
+@command{gnulib-tool --add-import} and
+@command{gnulib-tool --remove-import}.
+
+So, if you only want to use more Gnulib modules, simply invoke
+@command{gnulib-tool --add-import @var{new-modules}}. The list of
+modules that you pass after @samp{--add-import} is @emph{added} to the
+previous list of modules.
+
+Similarly, if you want to use fewer Gnulib modules, simply invoke
+@command{gnulib-tool --remove-import @var{unneeded-modules}}. The list
+of modules that you pass after @samp{--remove-import} is @emph{removed}
+from the previous list of modules. Note that if a module is then still
+needed as dependency of other modules, it will be used nevertheless.
+If you want to @emph{really} not use a module any more, regardless of
+whether other modules may need it, you need to use the @samp{--avoid}
+option.
+
+For other changes, such as different choices of @samp{--lib},
+@samp{--source-base} or @samp{--aux-dir}, the normal way is to
+modify manually the file @file{gnulib-cache.m4} in the M4 macros
+directory, then launch @samp{gnulib-tool --add-import}.