diff --git a/shared/challenges_markdown/three/part_two.md b/shared/challenges_markdown/three/part_two.md
index bcab930..f434806 100644
--- a/shared/challenges_markdown/three/part_two.md
+++ b/shared/challenges_markdown/three/part_two.md
@@ -1,27 +1,29 @@
-TODO: need to explain what the MST is!
+Now to really get your hands dirty.  It's time to build your own CAR.
 
-make a valid CAR file and upload it
+The CAR libraries listed in **Part one** above can help with this, or you can hand-craft every byte if you're that hardcore.
 
-the inspection will check for:
+Your CAR just needs to have one very specific record to pass this challenge:
 
 - **Collection:** `codes.advent.challenge.day`
-- **Record key:** `three`
-- **Field:** `verificationCode` set to `{{code}}`
+- **Rkey:** `three`
+
+Inside the record, we'll be looking for:
+
+- `"verificationCode": "{{code}}"`
+
+Any valid `DID` will do for the commit, and the signature won't be verified.
 
-any valid DID will do for the commit, and the signature won't be checked
 
 <form id="car-upload" method="post" action="/day/3/upload-car" enctype="multipart/form-data">
   <div id="drop-zone" style="border-radius: 0.5rem; padding: 1.25rem 1.5rem; text-align: center; cursor: pointer; max-width: 28rem;">
-    <p id="drop-label" style="display: flex; align-items: center; gap: 0.75rem; margin: 0">
-      Drop your car off here <small style="opacity: 0.667">(or click to browse)</small>
+    <p id="drop-label" style="display: flex; align-items: center; gap: 0.75rem; margin: 0; color: var(--color-primary)">
+      Drop your CAR off here <small style="opacity: 0.667">(or click to browse)</small>
     </p>
     <div id="drop-file-name" class="hidden" style="font-family: monospace; font-size: 0.875rem;"></div>
     <input id="car-input" type="file" name="car_file" accept=".car" class="hidden" required />
   </div>
 </form>
 
-TODO: remove the "check answer" button
-
 <script>
 (function() {
   const form = document.getElementById('car-upload');
@@ -73,7 +75,7 @@ TODO: remove the "check answer" button
 }
 #drop-zone.dragging,
 #drop-zone:hover {
-  background: hsla(0, 0%, 50%, 0.333);
+  background: hsla(0, 0%, 50%, 0.2);
   border-color: #22c55e;
 }
 #drop-label {
@@ -84,3 +86,12 @@ TODO: remove the "check answer" button
   opacity: 1;
 }
 </style>
+
+
+<hr/>
+
+<details>
+  <summary>MAJOR CHEATING hint for part 2</summary>
+
+  So&hellip; we really want you to build your own car. But. Tools like `goat` and `PDSls` do have a "download repo" function, and also a "create record" function, 👀
+</details>
diff --git a/shared/src/advent/challenges/day_three/day_three.rs b/shared/src/advent/challenges/day_three/day_three.rs
index 7e8d168..1f45a19 100644
--- a/shared/src/advent/challenges/day_three/day_three.rs
+++ b/shared/src/advent/challenges/day_three/day_three.rs
@@ -31,6 +31,10 @@ impl AdventChallenge for DayThree {
         true
     }
 
+    fn custom_submit_part_two(&self) -> bool {
+        true
+    }
+
     /// inject the car right on the page :sicko:
     async fn markdown_text_part_one(
         &self,
diff --git a/shared/src/advent/mod.rs b/shared/src/advent/mod.rs
index ed0611e..c4f203c 100644
--- a/shared/src/advent/mod.rs
+++ b/shared/src/advent/mod.rs
@@ -140,6 +140,12 @@ pub trait AdventChallenge {
         false
     }
 
+    /// Does this challenge's part two have its own submit mechanism?
+    /// Default is false (render the normal submit button)
+    fn custom_submit_part_two(&self) -> bool {
+        false
+    }
+
     /// The text Markdown for challenge 1
     async fn markdown_text_part_one(
         &self,
diff --git a/web/src/handlers/day.rs b/web/src/handlers/day.rs
index 9101c3d..cfb5f1a 100644
--- a/web/src/handlers/day.rs
+++ b/web/src/handlers/day.rs
@@ -192,6 +192,7 @@ pub async fn view_day_handler(
 
     let requires_code_input_part_one = challenge.requires_manual_verification_part_one();
     let requires_code_input_part_two = challenge.requires_manual_verification_part_two();
+    let custom_submit_part_two = challenge.custom_submit_part_two();
     let is_logged_in = session.logged_in();
 
     let template = match status {
@@ -206,6 +207,7 @@ pub async fn view_day_handler(
             part_two_submit_message: part_two_flash,
             requires_code_input_part_one,
             requires_code_input_part_two,
+            custom_submit_part_two,
             is_logged_in,
         },
         CompletionStatus::PartOne => {
@@ -222,6 +224,7 @@ pub async fn view_day_handler(
                 part_two_submit_message: part_two_flash,
                 requires_code_input_part_one,
                 requires_code_input_part_two,
+                custom_submit_part_two,
                 is_logged_in,
             }
         }
@@ -238,6 +241,7 @@ pub async fn view_day_handler(
                 part_two_submit_message: part_two_flash,
                 requires_code_input_part_one,
                 requires_code_input_part_two,
+                custom_submit_part_two,
                 is_logged_in,
             }
         }
diff --git a/web/src/templates/day.rs b/web/src/templates/day.rs
index 1eac772..36be20d 100644
--- a/web/src/templates/day.rs
+++ b/web/src/templates/day.rs
@@ -19,5 +19,8 @@ pub struct DayTemplate {
     pub requires_code_input_part_one: bool,
     pub requires_code_input_part_two: bool,
 
+    // prevent rendering the default "Check answer" button
+    pub custom_submit_part_two: bool,
+
     pub is_logged_in: bool,
 }
diff --git a/web/templates/day.askama.html b/web/templates/day.askama.html
index f743936..27abf95 100644
--- a/web/templates/day.askama.html
+++ b/web/templates/day.askama.html
@@ -109,7 +109,7 @@
                 <div class="card-actions justify-start mt-4">
                     {% if !is_logged_in %}
                         <a href="/login" class="btn btn-primary">Login to complete challenges</a>
-                    {% else if !challenge_two_completed %}
+                    {% else if !challenge_two_completed && !custom_submit_part_two %}
                         <form method="post" action="/day/{{ day }}">
                             {% if requires_code_input_part_two %}
                             <div class="join">
@@ -125,6 +125,7 @@
                                 <button class="btn btn-primary" type="submit">Check answer</button>
                             {% endif %}
                         </form>
+                    {% else if !challenge_two_completed %}
                     {% else %}
                         <div class="badge badge-success badge-lg gap-2">
                             <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" class="inline-block w-4 h-4 stroke-current"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M5 13l4 4L19 7"></path></svg>