diff --git a/Library/Homebrew/cleanup.rb b/Library/Homebrew/cleanup.rb
index 0503882cc7..cc12be3886 100644
--- a/Library/Homebrew/cleanup.rb
+++ b/Library/Homebrew/cleanup.rb
@@ -7,7 +7,6 @@ require "cask/cask_loader"
 require "set"
 
 CLEANUP_DEFAULT_DAYS = 30
-CLEANUP_MAX_AGE_DAYS = 120
 
 module CleanupRefinement
   refine Pathname do
@@ -132,7 +131,7 @@ module Homebrew
       @args = args
       @dry_run = dry_run
       @scrub = scrub
-      @days = days || CLEANUP_MAX_AGE_DAYS
+      @days = days || Homebrew::EnvConfig.cleanup_max_age_days.to_i
       @cache = cache
       @cleaned_up_paths = Set.new
     end
diff --git a/Library/Homebrew/cmd/cleanup.rb b/Library/Homebrew/cmd/cleanup.rb
index 9b106947a9..3f8481c8e6 100644
--- a/Library/Homebrew/cmd/cleanup.rb
+++ b/Library/Homebrew/cmd/cleanup.rb
@@ -8,12 +8,14 @@ module Homebrew
 
   def cleanup_args
     Homebrew::CLI::Parser.new do
+      days = Homebrew::EnvConfig::ENVS[:HOMEBREW_CLEANUP_MAX_AGE_DAYS][:default]
       usage_banner <<~EOS
         `cleanup` [<options>] [<formula>|<cask>]
 
         Remove stale lock files and outdated downloads for all formulae and casks,
         and remove old versions of installed formulae. If arguments are specified,
-        only do this for the given formulae and casks.
+        only do this for the given formulae and casks. Removes all downloads more than
+        #{days} days old. This can be adjusted with `HOMEBREW_CLEANUP_MAX_AGE_DAYS`.
       EOS
       flag   "--prune=",
              description: "Remove all cache files older than specified <days>."
diff --git a/Library/Homebrew/env_config.rb b/Library/Homebrew/env_config.rb
index 793e3e698e..14bb6e5a3a 100644
--- a/Library/Homebrew/env_config.rb
+++ b/Library/Homebrew/env_config.rb
@@ -50,6 +50,10 @@ module Homebrew
                       "Linux: `$XDG_CACHE_HOME/Homebrew` or `$HOME/.cache/Homebrew`.",
         default:      HOMEBREW_DEFAULT_CACHE,
       },
+      HOMEBREW_CLEANUP_MAX_AGE_DAYS:      {
+        description: "Cleanup all cached files older than this many days.",
+        default:     120,
+      },
       HOMEBREW_COLOR:                     {
         description: "If set, force colour output on non-TTY outputs.",
         boolean:     true,
diff --git a/docs/Manpage.md b/docs/Manpage.md
index 120e1cee70..979448a0c3 100644
--- a/docs/Manpage.md
+++ b/docs/Manpage.md
@@ -60,7 +60,8 @@ Control Homebrew's anonymous aggregate user behaviour analytics. Read more at
 
 Remove stale lock files and outdated downloads for all formulae and casks, and
 remove old versions of installed formulae. If arguments are specified, only do
-this for the given formulae and casks.
+this for the given formulae and casks. Removes all downloads more than 120 days
+old. This can be adjusted with `HOMEBREW_CLEANUP_MAX_AGE_DAYS`.
 
 * `--prune`:
   Remove all cache files older than specified *`days`*.
@@ -1223,6 +1224,11 @@ Note that environment variables must have a value set to be detected. For exampl
 
     *Default:* macOS: `$HOME/Library/Caches/Homebrew`, Linux: `$XDG_CACHE_HOME/Homebrew` or `$HOME/.cache/Homebrew`.
 
+  * `HOMEBREW_CLEANUP_MAX_AGE_DAYS`:
+    Cleanup all cached files older than this many days.
+
+    *Default:* `120`.
+
   * `HOMEBREW_COLOR`:
     If set, force colour output on non-TTY outputs.
 
diff --git a/manpages/brew.1 b/manpages/brew.1
index 6a7878449c..3fcac119eb 100644
--- a/manpages/brew.1
+++ b/manpages/brew.1
@@ -54,7 +54,7 @@ Control Homebrew\'s anonymous aggregate user behaviour analytics\. Read more at
     Regenerate the UUID used for Homebrew\'s analytics\.
 .
 .SS "\fBcleanup\fR [\fIoptions\fR] [\fIformula\fR|\fIcask\fR]"
-Remove stale lock files and outdated downloads for all formulae and casks, and remove old versions of installed formulae\. If arguments are specified, only do this for the given formulae and casks\.
+Remove stale lock files and outdated downloads for all formulae and casks, and remove old versions of installed formulae\. If arguments are specified, only do this for the given formulae and casks\. Removes all downloads more than 120 days old\. This can be adjusted with \fBHOMEBREW_CLEANUP_MAX_AGE_DAYS\fR\.
 .
 .TP
 \fB\-\-prune\fR
@@ -1560,6 +1560,13 @@ Use the specified directory as the download cache\.
 \fIDefault:\fR macOS: \fB$HOME/Library/Caches/Homebrew\fR, Linux: \fB$XDG_CACHE_HOME/Homebrew\fR or \fB$HOME/\.cache/Homebrew\fR\.
 .
 .TP
+\fBHOMEBREW_CLEANUP_MAX_AGE_DAYS\fR
+Cleanup all cached files older than this many days\.
+.
+.IP
+\fIDefault:\fR \fB120\fR\.
+.
+.TP
 \fBHOMEBREW_COLOR\fR
 If set, force colour output on non\-TTY outputs\.
 .