diff --git a/src/calibre/ebooks/mobi/reader/mobi8.py b/src/calibre/ebooks/mobi/reader/mobi8.py
index d871517178..7c5fbbe4f9 100644
--- a/src/calibre/ebooks/mobi/reader/mobi8.py
+++ b/src/calibre/ebooks/mobi/reader/mobi8.py
@@ -61,7 +61,8 @@ def reverse_tag_iter(block):
 
 class Mobi8Reader(object):
 
-    def __init__(self, mobi6_reader, log):
+    def __init__(self, mobi6_reader, log, for_tweak=False):
+        self.for_tweak = for_tweak
         self.mobi6_reader, self.log = mobi6_reader, log
         self.header = mobi6_reader.book_header
         self.encrypted_fonts = []
@@ -459,6 +460,20 @@ class Mobi8Reader(object):
         def exclude(path):
             return os.path.basename(path) == 'debug-raw.html'
 
+        # If there are no images then the azw3 input plugin dumps all
+        # binary records as .unknown images, remove them
+        if self.for_tweak and os.path.exists('images') and os.path.isdir('images'):
+            files = os.listdir('images')
+            unknown = [x for x in files if x.endswith('.unknown')]
+            if len(files) == len(unknown):
+                [os.remove('images/'+f) for f in files]
+
+        if self.for_tweak:
+            try:
+                os.remove('debug-raw.html')
+            except:
+                pass
+
         opf.create_manifest_from_files_in([os.getcwdu()], exclude=exclude)
         for entry in opf.manifest:
             if entry.mime_type == 'text/html':
diff --git a/src/calibre/ebooks/oeb/polish/container.py b/src/calibre/ebooks/oeb/polish/container.py
index c5c0c5e16e..b8fd8e2c18 100644
--- a/src/calibre/ebooks/oeb/polish/container.py
+++ b/src/calibre/ebooks/oeb/polish/container.py
@@ -1022,20 +1022,9 @@ def do_explode(path, dest):
         mr = MobiReader(stream, default_log, None, None)
 
         with CurrentDir(dest):
-            mr = Mobi8Reader(mr, default_log)
+            mr = Mobi8Reader(mr, default_log, for_tweak=True)
             opf = os.path.abspath(mr())
             obfuscated_fonts = mr.encrypted_fonts
-            # If there are no images then the azw3 input plugin dumps all
-            # binary records as .unknown images, remove them
-            if os.path.exists('images') and os.path.isdir('images'):
-                files = os.listdir('images')
-                unknown = [x for x in files if x.endswith('.unknown')]
-                if len(files) == len(unknown):
-                    [os.remove('images/'+f) for f in files]
-            try:
-                os.remove('debug-raw.html')
-            except:
-                pass
 
     return opf, obfuscated_fonts