Solving previous years' question papers of the UPSC Mathematics optional subject can indeed be a beneficial strategy for improving conceptual clarity. Here's how:

1. Understanding Exam Pattern:
- By solving previous years' question papers, you can familiarize yourself with the exam pattern, question types, and difficulty level.
- It helps you understand the distribution of marks across various topics, allowing you to allocate your time and efforts accordingly.

2. Identifying Important Topics:
- Analyzing previous years' question papers helps you identify the recurring topics and concepts that have been frequently asked.
- This enables you to prioritize your study and focus more on the important areas, ensuring a better grasp of the subject.

3. Reinforcing Concepts:
- Solving previous years' question papers provides an opportunity to revise and reinforce the core concepts of the subject.
- It helps you apply theoretical knowledge to practical problems, enhancing your understanding and retention of the concepts.

4. Time Management:
- Practicing previous years' papers aids in developing effective time management skills, as you get accustomed to the time constraints of the actual exam.
- It allows you to assess how long it takes to solve different types of questions, enabling you to allocate time appropriately during the exam.

5. Building Confidence:
- Solving previous years' papers gives you a sense of familiarity and boosts your confidence.
- As you become more comfortable with the exam format and question patterns, you develop a positive mindset, reducing exam anxiety and strengthening your performance.

6. Identifying Weak Areas:
- By solving previous years' papers, you can identify your weak areas and focus on improving them.
- It helps you gauge your level of preparation and highlights the topics that require more attention and practice.

7. Practicing Exam-like Conditions:
- Solving previous years' papers under simulated exam conditions helps you experience the pressure and time constraints of the actual exam.
- It prepares you mentally and emotionally, making you more confident and composed during the real exam.

In conclusion, solving previous years' question papers of the UPSC Mathematics optional subject is an effective strategy to improve conceptual clarity. It helps in understanding the exam pattern, identifying important topics, reinforcing concepts, managing time, building confidence, identifying weak areas, and practicing under exam-like conditions. Regular practice with these papers can significantly enhance your performance and increase your chances of success in the UPSC examination.