Unlocking the "Inventing the Past" quest in The Sims 4's Blast from the Past event requires locating Plathinum and Ironyum. Fortunately, this is a straightforward process.
This guide explains how to quickly find these resources:
To obtain Plathinum and Ironyum, simply locate areas with rocks and dirt mounds – parks are ideal. Pause the game to thoroughly scan the area. Once you spot a suitable mound, dig it up. It might take a few attempts, but you'll eventually unearth both Plathinum and Ironyum, unlocking the next quest stage: building the Time Travel Component.
If dirt mounds are scarce, speeding up in-game time can encourage their faster generation. However, avoid prolonged periods of sped-up time to prevent missing digging opportunities.
All Blast from the Past Event Rewards:

The Blast from the Past event offers a range of rewards across four weeks. Here's a summary:
Week 1: Retro Deco Phone Set, Relevart Time Walkers, The Yesterday Set floor tiles, The Future’s So Bright “Sun” Glasses, The Fun-Fun Inflatable Set, Part One.
Week 2: Get Up! Alarm Clock, Be “The Emit” full body outfit, Bigger Gatherings Banquet, The Relevart Neck Stabilizer bow tie.
Week 3: The Fun-Fun Inflatable Set, Part Two, Dina Caliente’s LBD, New Retro Station Songs, Sticky Fingers aspiration.
Week 4: Surprise Birthday Cake, The ElectroDance Floor.
With the event extended, you have ample time to complete all quests. However, early completion offers bragging rights!
This concludes the guide on finding Plathinum and Ironyum in The Sims 4's Blast from the Past event. For future updates and event information, check the 2025 roadmap.
The Sims 4 is available now on PlayStation, Xbox, and PC.