diff --git a/pyproject.toml b/pyproject.toml
index 9cb6801..4974087 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -65,7 +65,13 @@ build-frontend = { name = "build[uv]", args = ["--no-isolation"] }
 build-verbosity = 1
 test-requires = ["pytest", "pytest-cov", "PyYAML", "scipy"]
 before-build = [
-    "pip install pip-tools && pip-compile --all-build-deps -o \"{project}/build-reqs.txt\" && pip install -r \"{project}/build-reqs.txt\""
+    # These two lines get the build requirements from `pyproject.toml`
+    "pip install pip-tools",
+    "pip-compile --all-build-deps -o \"{project}/build-reqs.txt\" \"{project}/pyproject.toml\"",
+    # We install them since we're building without isolation.
+    "pip install -r \"{project}/build-reqs.txt\"",
+    # We remove the residual *.so files specific to a CPython version from the last build.
+    "find \"{project}\" -name *.cpython-*.so -type f -delete"
 ]
 before-test = "uv pip install --no-deps sparse@git+https://github.com/pydata/sparse.git"
 test-command = "SPARSE_BACKEND=\"MLIR\" python -m pytest --pyargs sparse.mlir_backend"