Deduplicating data means keeping only a single occurrence of every piece of data. Applied to cloud storage, it can significantly reduce physical file sizes, reduce storage costs and accelerate I/O. In this talk, I will cover how Data Engineers can use open-source tools to deduplicate Parquet data with Parquet Content Defined Chunking (CDC) and how it works under the hood (minutes 0-10). I'll also present simple examples as well as real-world examples from the 100PB+ of datasets and buckets on Hugging Face (minutes 10-20).