diff --git a/lib/utils/sanitization.js b/lib/utils/sanitization.js
--- a/lib/utils/sanitization.js
+++ b/lib/utils/sanitization.js
@@ -72,10 +72,17 @@
   'curve25519',
   'picklingKey',
   'pickledAccount',
+  'commServicesAccessToken',
+  'blobHash',
+  'blobHolder',
+  'holder',
+  'thumbnailHolder',
+  'encryptionKey',
 ]);
 
 // eg {"memberIDs":["123", "456"]} => {"memberIDs":["redacted", "redacted"]}
 const keysWithArraysToBeRedacted = new Set([
+  'devices',
   'memberIDs',
   'messageIDs',
   'already_friends',
@@ -109,6 +116,10 @@
   'thumbnailURI',
 ]);
 
+// eg {"uri":"comm-blob-service://1a2b3c4d5e6f"}
+// => {"uri":"comm-blob-service://placeholder"}
+const keysWithBlobURIsToBeReplaced = new Set(['blobURI, thumbnailBlobURI']);
+
 // (special case that redacts triply-linked [] to handle `daysToEntries` )
 // eg "daysToEntries":{"2020-12-29":["123"]}
 // => "daysToEntries":{"2020-12-29":["redacted"]}
@@ -132,6 +143,10 @@
   return 'https://comm.app/images/placeholder.png';
 }
 
+function placeholderBlobURI(): string {
+  return 'comm-blob-service://placeholder';
+}
+
 function scrambleText(str: string): string {
   const arr = [];
   for (const char of new String(str)) {
@@ -233,6 +248,8 @@
       obj[k] = scrambleText(obj[k]);
     } else if (keysWithImageURIsToBeReplaced.has(k)) {
       obj[k] = placeholderImageURI();
+    } else if (keysWithBlobURIsToBeReplaced.has(k)) {
+      obj[k] = placeholderBlobURI();
     } else if (keysWithArraysToBeRedacted.has(k)) {
       obj[k] = obj[k].map(redactionHelpers.redactString);
     } else if (typeof obj[k] === 'object') {