diff --git a/docs/building.sgml b/docs/building.sgml
index eebe7aa0cb4c570c3058855818c59c73df5d1aa9..99a36ac872a74cb895e137c7f4a88cd39ea24af0 100644
--- a/docs/building.sgml
+++ b/docs/building.sgml
@@ -1230,7 +1230,8 @@ programs.  It also builds the necessary tools for compilation to proceed.
 You should say <Command>gmake boot</Command> right after configuring your build tree,
 but note that this is a one-off, i.e., there's no need to re-do
 <Command>gmake boot</Command> if you should re-configure your build tree at a later
-stage (no harm caused if you do though).
+stage (no harm caused if you do though).  Notably, you should say
+<Command>gmake boot</Command> before you say <Command>gmake clean</Command>.
 </Para>
 </ListItem></VarListEntry>
 <VarListEntry>
@@ -1268,11 +1269,11 @@ reverses the effect of <Literal>install</Literal>.
 <Term><Literal>clean</Literal>:</Term>
 <ListItem>
 <Para>
-Delete all files from the current directory that are normally
-created by building the program.  Don't delete the files that
-record the configuration. Also preserve files that could be made
-by building, but normally aren't because the distribution comes
-with them.</para>
+Delete all files from the current directory that are normally created
+by building the program.  Don't delete the files that record the
+configuration, or files generated by <Command>gmake boot</Command>.
+Also preserve files that could be made by building, but normally
+aren't because the distribution comes with them.</para>
 </ListItem></VarListEntry>
 
 <varlistentry>