diff --git a/web/src/wasm-core.js b/web/src/wasm-core.js
index 513a692..14e0526 100644
--- a/web/src/wasm-core.js
+++ b/web/src/wasm-core.js
@@ -533,6 +533,7 @@ function installOpfsWorkspace(module, options) {
       } else {
         await removeOpfsFileEntry(workspacePath, `${path}.bak`);
       }
+      cleanupLinuxCncParameterFiles(module);
       return data;
     },
     async removeFile(path) {
diff --git a/web/test-browser-wasm-smoke-opfs-parameter-sections.js b/web/test-browser-wasm-smoke-opfs-parameter-sections.js
index 83fb561..0d22989 100644
--- a/web/test-browser-wasm-smoke-opfs-parameter-sections.js
+++ b/web/test-browser-wasm-smoke-opfs-parameter-sections.js
@@ -16,13 +16,13 @@ export async function runBrowserOpfsParameterSections(context, simulator) {
     withSmokeSimulator,
   } = context;
   const backend = { backend: "linuxcnc-rs274" };
-  const parseWithParameters = (program, path) =>
-    simulator.parseWithParameterFile(program, path, "linuxcnc", backend);
+  const parseWithParameters = (program, path) => simulator.parseWithParameterFile(program, path, "linuxcnc", backend);
 
   await runSection("opfs parameter save", async () => {
     await simulator.parseWithParameterFile("G21 G90\nG0 X1\nG28.1\nM30\n", "parameters/rs274ngc.var", "linuxcnc", backend);
     const opfsParameterFile = await readOpfsText(simulator, "parameters/rs274ngc.var");
     expectIncludes(opfsParameterFile, "5161\t1.000000", "LinuxCNC parameter file was not persisted into OPFS");
+    expectWasmFilesMissing(simulator.fs.module.FS, ["rs274ngc.var", "rs274ngc.var.new", "rs274ngc.var.bak"], (parameterPath) => `LinuxCNC parameter scratch file remained outside OPFS after save: ${parameterPath}`);
   });
 
   await runSection("opfs parameter restore in new instance", async () => {
@@ -84,6 +84,7 @@ export async function runBrowserOpfsParameterSections(context, simulator) {
     const opfsParameterBackup = await readOpfsText(simulator, "parameters/backup-bridge.var.bak");
     expectIncludes(opfsParameterBackup, "5161\t1.000000",
       "LinuxCNC parameter backup file was not bridged into OPFS");
+    expectWasmFilesMissing(simulator.fs.module.FS, ["rs274ngc.var", "rs274ngc.var.new", "rs274ngc.var.bak"], (parameterPath) => `LinuxCNC parameter scratch file remained outside OPFS after backup bridge: ${parameterPath}`);
   });
 
   await runSection("opfs parameter backup after existing save", async () => {