diff --git a/CHANGELOG.md b/CHANGELOG.md
index 212c341..81d2103 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ Format: [Keep a Changelog](https://keepachangelog.com/en/1.1.0/)
 
 ## [Unreleased]
 
+### Removed
+- Dead module `philanthropy/preprocessing/_solicitation_window.py`. The
+  deprecated alias `SolicitationWindowTransformer` already resolved only
+  through `__getattr__` in `__init__.py`; the file was unimported and
+  dragged coverage to 0%. Closes #153.
+
 ### Fixed
 - `GratefulPatientFeaturizer` now reports one fallback `general` service line
   per known donor when the encounter table omits the service-line column.
diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index a571edf..c882b6b 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -76,3 +76,4 @@ too; say so in the PR and it stays out.
 Not sure where to start? See
 [CONTRIBUTING.md](CONTRIBUTING.md) and the
 [good first issues](https://github.com/PhilanthroPy-Project/PhilanthroPy/issues?q=is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22).
+- [@haas26p-ctrl](https://github.com/haas26p-ctrl): deleted the unused `_solicitation_window` alias module ([#153](https://github.com/PhilanthroPy-Project/PhilanthroPy/issues/153)).
diff --git a/philanthropy/preprocessing/__init__.py b/philanthropy/preprocessing/__init__.py
index e7014fc..3b8e93e 100755
--- a/philanthropy/preprocessing/__init__.py
+++ b/philanthropy/preprocessing/__init__.py
@@ -37,8 +37,12 @@
 ]
 
 
+# Deprecated aliases resolve through __getattr__ (PEP 562) to the same class
+# object as the canonical name — not a subclass — so isinstance/clone behave
+# as before. They are removed in 1.0.0. No separate alias modules: those would
+# be unimported dead code (the alias never loads them).
 _DEPRECATED_ALIASES = {
-    # alias -> (canonical name, module attribute)
+    # alias -> canonical attribute name in this module's globals()
     "SolicitationWindowTransformer": "DischargeToSolicitationWindowTransformer",
 }
 
diff --git a/philanthropy/preprocessing/_solicitation_window.py b/philanthropy/preprocessing/_solicitation_window.py
deleted file mode 100755
index 8eda91b..0000000
--- a/philanthropy/preprocessing/_solicitation_window.py
+++ /dev/null
@@ -1,16 +0,0 @@
-"""
-philanthropy.preprocessing._solicitation_window
-================================================
-Deprecated alias for :class:`DischargeToSolicitationWindowTransformer`.
-
-Two public names for one transformer inflate the API surface without adding
-capability, so the alias goes away in 1.0.0. It resolves to the same class
-object rather than a subclass, so ``isinstance`` and ``clone`` behave exactly as
-before; the deprecation warning is emitted on attribute access by the
-subpackage's module-level ``__getattr__`` (PEP 562).
-"""
-
-from ._discharge_window import DischargeToSolicitationWindowTransformer
-
-#: Deprecated. Use ``DischargeToSolicitationWindowTransformer``.
-SolicitationWindowTransformer = DischargeToSolicitationWindowTransformer