{code}
 ./configure_uw -DCLIPPED:BOOL=ON
 {endcode}
-*: Builds by default cache the externals in /scratch/condor-externals. If you are sharing the machine with others, you may collide and have problems.  To fix this, add this to your invocation of configure_uw
-{code}
--DEXTERNAL_STAGE:PATH=/path/to/a/private/directory
-{endcode}
+*: Builds by default cache the externals under =bld_external/= in your build directory. You can change where the externals are installed by setting the environment variable =CONDOR_BLD_EXTERNAL_STAGE= to point to the desired location. As a given external always builds the same on a given platform, using a single externals location for several build directories can save unnecessary recompilation.
 
 {section: Building your source}