diff --git a/README.md b/README.md
index 806930c..40d9a81 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,10 @@
+1. [7digital.rb](#7digitalrb)
+2. [mock\_server.rb](#mock_serverrb)
+3. [read\_logs.rb](#read_logsrb)
+4. [cross\_toolchain.rb](#cross_toolchainrb)
+5. [rename.rb](#renamerb)
+6. [tea-cleaner](#tea-cleaner)
+
 ## 7digital.rb
 
 7digital sells digital music but they can't handle files with non-English names.
@@ -64,3 +71,37 @@ Call the `rename.rb` without arguments to see the usage information and an
 example.
 
 ## tea-cleaner
+
+`tea-cleaner` tries to detect spam accounts on a gitea instance and can remove
+them automatically.
+
+### Run instructions
+
+See `tea-cleaner.toml.dist` for a description of the available configuration.
+Copy this file to `config/tea-cleaner.toml` and change at least `token` and
+`server` values. After that if you just run `tea-cleaner` it will give a list
+of user accounts which look suspicious to it. Rerunning the command with the
+`--live-run` flag will purge the listed accounts and all their activities,
+assuming the given token has amdinistrative access to the Gitea instance.
+
+Run `tea-cleanr --help` to see all available command line options. 
+
+### Applied rules
+
+Critical:
+
+- The account is elder than a month and the user hasn't logged in since then.
+- User information contains banned words (can be adjusted in the configuration file).
+- User's homepage contains percent encoded symbols.
+
+Possible:
+
+- User filled fields for personal information: description and website.
+- The mail address domain is unusual (can be adjusted in the configuration file).
+
+The accounts that violate one of the critical rules are marked for removal
+right away. Other checks trigger an additional lookup for the last user
+activities. If everything user did was creating an empty repository, these
+accounts are marked for removal as well.
+
+The rules are based on my invastigation of spam accounts on this instance.
diff --git a/tea-cleaner/Main.hs b/tea-cleaner/Main.hs
index e9fead1..5433394 100644
--- a/tea-cleaner/Main.hs
+++ b/tea-cleaner/Main.hs
@@ -1,3 +1,7 @@
+{- This Source Code Form is subject to the terms of the Mozilla Public License,
+   v. 2.0. If a copy of the MPL was not distributed with this file, You can
+   obtain one at https://mozilla.org/MPL/2.0/. -}
+
 module Main
     ( main
     ) where
diff --git a/tea-cleaner/TeaCleaner/Client.hs b/tea-cleaner/TeaCleaner/Client.hs
index 5afd6a5..fae3e6a 100644
--- a/tea-cleaner/TeaCleaner/Client.hs
+++ b/tea-cleaner/TeaCleaner/Client.hs
@@ -1,3 +1,7 @@
+{- This Source Code Form is subject to the terms of the Mozilla Public License,
+   v. 2.0. If a copy of the MPL was not distributed with this file, You can
+   obtain one at https://mozilla.org/MPL/2.0/. -}
+
 module TeaCleaner.Client
     ( Activity(..)
     , User(..)
diff --git a/tea-cleaner/TeaCleaner/Configuration.hs b/tea-cleaner/TeaCleaner/Configuration.hs
index 1d2db32..dad1450 100644
--- a/tea-cleaner/TeaCleaner/Configuration.hs
+++ b/tea-cleaner/TeaCleaner/Configuration.hs
@@ -1,3 +1,7 @@
+{- This Source Code Form is subject to the terms of the Mozilla Public License,
+   v. 2.0. If a copy of the MPL was not distributed with this file, You can
+   obtain one at https://mozilla.org/MPL/2.0/. -}
+
 module TeaCleaner.Configuration
     ( ProgramOptions(..)
     , Settings(..)
diff --git a/tea-cleaner/TeaCleaner/Filter.hs b/tea-cleaner/TeaCleaner/Filter.hs
index 658606d..434825a 100644
--- a/tea-cleaner/TeaCleaner/Filter.hs
+++ b/tea-cleaner/TeaCleaner/Filter.hs
@@ -1,3 +1,7 @@
+{- This Source Code Form is subject to the terms of the Mozilla Public License,
+   v. 2.0. If a copy of the MPL was not distributed with this file, You can
+   obtain one at https://mozilla.org/MPL/2.0/. -}
+
 module TeaCleaner.Filter
     ( FilterResult(..)
     , UserFilter(..)
diff --git a/tea-cleaner/TeaCleaner/Options.hs b/tea-cleaner/TeaCleaner/Options.hs
index 7353f8f..7965a97 100644
--- a/tea-cleaner/TeaCleaner/Options.hs
+++ b/tea-cleaner/TeaCleaner/Options.hs
@@ -1,3 +1,7 @@
+{- This Source Code Form is subject to the terms of the Mozilla Public License,
+   v. 2.0. If a copy of the MPL was not distributed with this file, You can
+   obtain one at https://mozilla.org/MPL/2.0/. -}
+
 module TeaCleaner.Options
     ( jsonOptions
     ) where