Clean up challenges.md: Remove emojis and tips section

- Remove emojis from all markdown headings for cleaner appearance
- Delete 'Tips for Success' section to streamline content
- Maintain essential challenge rules and requirements

challenges.md

@@ -5,13 +5,13 @@ include_toc: true
 
 # 3D Print Meetup Challenges
 
-## 🗓️ October 2025 Challenge: "Is it Glass or Clearly Natural?"
+## October 2025 Challenge: "Is it Glass or Clearly Natural?"
 
-### 🎯 Challenge Overview
+### Challenge Overview
 
 Experience the clarity of 3D Fuel's "Clearly Natural" filament in this transparency-focused challenge! Participants will attempt to create the clearest possible print, testing the limits of clear filament printing techniques.
 
-### 📋 Challenge Rules
+### Challenge Rules
 
 #### Materials & Constraints
 
@@ -51,7 +51,7 @@ Experience the clarity of 3D Fuel's "Clearly Natural" filament in this transpare
 - **Community Voting**: People's choice award for favorite clear print
 - **Technical Review**: Expert panel assessment of print quality and technique
 
-### 🏆 Prizes & Recognition
+### Prizes & Recognition
 
 #### Awards
 
@@ -67,7 +67,7 @@ Experience the clarity of 3D Fuel's "Clearly Natural" filament in this transpare
 - Video documentation of winning techniques
 - Settings and process sharing for community learning
 
-### 📅 Timeline
+### Timeline
 
 - **Challenge Announcement**: October 1, 2025
 - **Model Specification Released**: October 13, 2025
@@ -75,7 +75,7 @@ Experience the clarity of 3D Fuel's "Clearly Natural" filament in this transpare
 - **Judging Period**: October 29-30, 2025
 - **Winner Announcement**: October 31, 2025
 
-### <EFBFBD> Creating the Cylinder Model
+### Creating the Cylinder Model
 
 #### Using Bambu Studio
 
@@ -104,11 +104,3 @@ Experience the clarity of 3D Fuel's "Clearly Natural" filament in this transpare
 - **FreeCAD**: Create cylinder with specified dimensions
 - **Any CAD Software**: Simple cylinder 25mm diameter × 50mm height
 
-### <20>💡 Tips for Success
-
-- **Vase Mode Settings**: Ensure single perimeter, no infill, no top layers
-- **Layer Height**: Experiment with smaller layer heights (0.1-0.2mm) for better clarity
-- **Print Speed**: Slower speeds in vase mode often improve surface quality
-- **Temperature Tuning**: Optimal temperature is critical for transparency
-- **Cooling**: Proper part cooling helps maintain wall quality in vase mode
-- **Post-Processing**: Light sanding or vapor smoothing can enhance clarity