How do I clean up inconsistent colours, sizes and materials across my catalogue?

Create canonical values for common attributes and map inconsistent entries to them—for example, deciding whether 'navy', 'navy blue' and 'dark navy' should remain distinct or roll up to one customer-facing colour. Apply the same approach to sizes, materials, units and product types. Use automated rules for obvious matches and review ambiguous cases manually. Preserve the original source value when needed, but keep the customer-facing and machine-readable catalogue normalised so filters, feeds and recommendations behave consistently.