diff --git a/lib/index.js b/lib/index.js
index 91f0b75..6d6e22e 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -83,23 +83,39 @@ class DBTangle extends MsgV3.Tangle {
   }
 
   /**
+   * Given a set of msgs (`msgIDs`) in this tangle, find all "deletable" and
+   * "erasable" msgs that precede that set.
+   *
+   * *Deletables* are msgs that precede `msgsIDs` but are not important in any
+   * validation path toward the root, and thus can be deleted.
+   *
+   * *Erasables* are msgs that precede `msgsIDs` and can be erased without
+   * losing a validation path toward the root.
    * @param {Array<string>} msgIDs
+   * @returns {{ deletables: Set<string>, erasables: Set<string> }}
    */
   getDeletablesAndErasables(...msgIDs) {
-    const erasableSet = new Set()
+    // Determine erasables
+    const erasables = new Set()
     const minimum = this.getMinimumAmong(msgIDs)
     for (const msgID of minimum) {
       const trail = this.shortestPathToRoot(msgID)
       for (const id of trail) {
-        erasableSet.add(id)
+        erasables.add(id)
       }
     }
+
+    // Determine deletables
+    const deletables = new Set()
     const sorted = this.topoSort()
-    const deletables = sorted.filter(
-      (id) =>
-        !erasableSet.has(id) && minimum.some((min) => this.precedes(id, min))
-    )
-    return { deletables, erasables: [...erasableSet] }
+    for (const msgID of sorted) {
+      if (erasables.has(msgID)) continue
+      if (minimum.some((min) => this.precedes(msgID, min))) {
+        deletables.add(msgID)
+      }
+    }
+
+    return { deletables, erasables }
   }
 }
 
@@ -929,7 +945,7 @@ function initDB(peer, config) {
 
   /**
    * @param {string} tangleID
-   * @returns {Tangle}
+   * @returns {DBTangle}
    */
   function getTangle(tangleID) {
     return new DBTangle(tangleID, records())
diff --git a/test/getTangle.test.js b/test/getTangle.test.js
index 50201c7..786b976 100644
--- a/test/getTangle.test.js
+++ b/test/getTangle.test.js
@@ -204,8 +204,8 @@ test('Tangle.getLipmaaSet', (t) => {
 test('Tangle.getDeletablesAndErasables basic', (t) => {
   const { deletables, erasables } = tangle.getDeletablesAndErasables(reply2)
 
-  assert.deepEqual(deletables, [reply1Hi], 'deletables')
-  assert.deepEqual(erasables, [reply1Lo, rootPost], 'erasables')
+  assert.deepEqual([...deletables], [reply1Hi], 'deletables')
+  assert.deepEqual([...erasables], [reply1Lo, rootPost], 'erasables')
 })
 
 test('Tangle.getDeletablesAndErasables with many inputs', (t) => {
@@ -214,8 +214,8 @@ test('Tangle.getDeletablesAndErasables with many inputs', (t) => {
     reply2
   )
 
-  assert.deepEqual(deletables, [reply1Hi], 'deletables')
-  assert.deepEqual(erasables, [reply1Lo, rootPost], 'erasables')
+  assert.deepEqual([...deletables], [reply1Hi], 'deletables')
+  assert.deepEqual([...erasables], [reply1Lo, rootPost], 'erasables')
 })
 
 test('Tangle.getDeletablesAndErasables with many inputs again', (t) => {
@@ -224,15 +224,15 @@ test('Tangle.getDeletablesAndErasables with many inputs again', (t) => {
     reply3Hi
   )
 
-  assert.deepEqual(deletables, [reply1Lo, reply1Hi, reply2], 'deletables')
-  assert.deepEqual(erasables, [rootPost], 'erasables')
+  assert.deepEqual([...deletables], [reply1Lo, reply1Hi, reply2], 'deletables')
+  assert.deepEqual([...erasables], [rootPost], 'erasables')
 })
 
 test('Tangle.getDeletablesAndErasables with lipmaa', (t) => {
   const { deletables, erasables } = tangle.getDeletablesAndErasables(reply3Lo)
 
-  assert.deepEqual(deletables, [reply1Lo, reply1Hi, reply2], 'deletables')
-  assert.deepEqual(erasables, [rootPost], 'erasables')
+  assert.deepEqual([...deletables], [reply1Lo, reply1Hi, reply2], 'deletables')
+  assert.deepEqual([...erasables], [rootPost], 'erasables')
 })
 
 test('Tangle.getMinimumAmong', (t) => {