--- a/browser/base/content/sanitize.js
+++ b/browser/base/content/sanitize.js
@@ -729,41 +729,28 @@ Sanitizer.clearPluginData = Task.async(f
 
     // Determine age range in seconds. (-1 means clear all.) We don't know
     // that range[1] is actually now, so we compute age range based
     // on the lower bound. If range results in a negative age, do nothing.
     let age = range ? (Date.now() / 1000 - range[0] / 1000000) : -1;
     if (!range || age >= 0) {
       let tags = ph.getPluginTags();
       for (let tag of tags) {
-        let refObj = {};
-        let probe = "";
-        if (/\bFlash\b/.test(tag.name)) {
-          probe = tag.loaded ? "FX_SANITIZE_LOADED_FLASH"
-                             : "FX_SANITIZE_UNLOADED_FLASH";
-          TelemetryStopwatch.start(probe, refObj);
-        }
         try {
           let rv = yield new Promise(resolve =>
             ph.clearSiteData(tag, null, FLAG_CLEAR_ALL, age, resolve)
           );
           // If the plugin doesn't support clearing by age, clear everything.
           if (rv == Components.results.NS_ERROR_PLUGIN_TIME_RANGE_NOT_SUPPORTED) {
             yield new Promise(resolve =>
               ph.clearSiteData(tag, null, FLAG_CLEAR_ALL, -1, resolve)
             );
           }
-          if (probe) {
-            TelemetryStopwatch.finish(probe, refObj);
-          }
         } catch (ex) {
           // Ignore errors from plug-ins
-          if (probe) {
-            TelemetryStopwatch.cancel(probe, refObj);
-          }
         }
       }
     }
   });
 
   try {
     // We don't want to wait for this operation to complete...
     promiseClearPluginData = promiseClearPluginData(range);

--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -9534,34 +9534,16 @@
   "FX_SANITIZE_COOKIES_2": {
     "alert_emails": ["firefox-dev@mozilla.org"],
     "expires_in_version": "never",
     "kind": "exponential",
     "high": 30000,
     "n_buckets": 20,
     "description": "Sanitize: Time it takes to sanitize firefox cookies (ms). A subset of FX_SANITIZE_COOKIES."
   },
-  "FX_SANITIZE_LOADED_FLASH": {
-    "alert_emails": ["firefox-dev@mozilla.org"],
-    "bug_numbers": [1251469],
-    "expires_in_version": "55",
-    "kind": "exponential",
-    "high": 30000,
-    "n_buckets": 20,
-    "description": "Sanitize: Time it takes to sanitize Flash when it's already loaded (ms). A subset of FX_SANITIZE_PLUGINS."
-  },
-  "FX_SANITIZE_UNLOADED_FLASH": {
-    "alert_emails": ["firefox-dev@mozilla.org"],
-    "bug_numbers": [1251469],
-    "expires_in_version": "55",
-    "kind": "exponential",
-    "high": 30000,
-    "n_buckets": 20,
-    "description": "Sanitize: Time it takes to sanitize Flash when it's not yet loaded (ms). A subset of FX_SANITIZE_PLUGINS."
-  },
   "FX_SANITIZE_HISTORY": {
     "alert_emails": ["firefox-dev@mozilla.org"],
     "expires_in_version": "never",
     "kind": "exponential",
     "high": 30000,
     "n_buckets": 20,
     "description": "Sanitize: Time it takes to sanitize history (ms)"
   },