diff --git a/usr/local/bin/synapse-clear-state.sh b/usr/local/bin/synapse-clear-state.sh
index 752562f..a3effa7 100755
--- a/usr/local/bin/synapse-clear-state.sh
+++ b/usr/local/bin/synapse-clear-state.sh
@@ -3,10 +3,16 @@
 # THIS SCRIPT IS REPLACED BY "synapse_auto_compressor" see:
 # https://github.com/matrix-org/rust-synapse-compress-state for details.
 #
-# run it via:
-#   synapse_auto_compressor -p "user=postgres dbname=matrix host=/var/run/postgresql" -c 500 -n 100
+# Before you execude the script better remove all rooms without local members.
+# see script "matrix-remove-empty-rooms.sh".
 #
-# after all you rooms are processed you can run a:
+# now you can run synapse-compress-state via:
+#   synapse_auto_compressor -p "user=postgres dbname=matrix host=/var/run/postgresql" -c 500 -n 100
+# on a HS with ~50.000 rooms you need to run the script round about 500 times:
+#   for run in {1..500}; do sudo -u postgres synapse_auto_compressor -p "user=postgres dbname=matrix host=/var/run/postgresql" -c 500 -n 100; done
+# you can see the already "initialized" rooms in the DB table "state_compressor_progress".
+#
+# after all rooms are processed you can run a:
 #   REINDEX (VERBOSE) DATABASE CONCURRENTLY DATABASENAME
 # to free your discspace.
 #