It seems there was an issue retrieving the specific discussion from Reddit. However, I can summarize some popular choices of clay bar kits often recommended on the r/AutoDetailing community, based on general feedback and reviews.

Popular Clay Bar Kits on r/AutoDetailing:

1. Mothers California Gold Clay Bar Kit:

   This is a popular choice due to its affordability and ease of use. It typically includes two 100-gram clay bars, a quick detailer (clay lubricant), and a microfiber towel.Users like it for its effectiveness at removing contaminants without being too aggressive, making it ideal for beginners.

2. Meguiar’s Smooth Surface Clay Kit:

   A commonly recommended kit, known for its smooth and pliable clay that’s easy to work with.It includes two 80-gram clay bars, a quick detailer for lubrication, and a microfiber towel.It’s praised for being a great all-around clay kit, especially for those new to clay barring.

3. Chemical Guys Medium Clay Bar Kit:

   For those looking for a more professional-grade product, this kit offers a medium-grade clay bar for tougher contamination.The kit includes a bar and a lubricant. The clay is known for being durable and highly effective on moderate contamination.Many in the community prefer Chemical Guys for the variety of clay bar grades available (fine, medium, heavy), depending on the needs of the car's surface.

4. Griot’s Garage Paint Cleaning Clay Kit:

   Another highly rated kit, especially for more experienced detailers. It’s gentle on paint but effective at removing stubborn contaminants.The kit typically includes a clay bar and Griot’s Speed Shine as the lubricant.It’s often praised for its high-quality clay and lubricants, making it a favorite among enthusiasts.

5. Auto Finesse Clay Bar Kit:

   Frequently recommended for its smooth performance and high-quality lubricant. The clay bar is soft and easy to use, making it suitable for frequent detailing.Auto Finesse products are generally regarded for their premium quality, and the clay bar kit is no exception.

General Advice From r/AutoDetailing:

• Lubrication is Key: Always use plenty of lubricant (such as a quick detailer) to prevent the clay bar from sticking and marring the paint.
• Grade of Clay: Choose a fine-grade clay for lightly contaminated surfaces and a medium/heavy clay for more stubborn contaminants. If you are unsure, start with a fine grade to minimize the risk of damaging the paint.
• Knead the Clay: Frequently fold and knead the clay bar to expose a clean surface, which will help prevent scratching.

The Mothers and Meguiar’s kits are generally the go-to recommendations for beginners, while Chemical Guys and Auto Finesse tend to cater more to detailers who are looking for a higher grade product.

Let me know if you'd like more details on any of these options!