You don’t need to replace it yet — most of these stains can be lifted unless they’re etched into the plastic. Based on what you described (yellow/brown underside on plastic/melamine), here’s a realistic, step-by-step “try this before replacing” plan:

🧼 Step 1 — Start Simple (often surprisingly effective)
Hot water + dish soap
Non-scratch sponge
Scrub firmly for a few minutes.
👉 This removes surface urine/mineral buildup first before stronger methods

⚗️ Step 2 — Baking Soda + Vinegar (best first “deep clean”)
Sprinkle baking soda
Spray/pour white vinegar
Let it fizz and sit 10–15 min
Scrub + rinse
👉 This combo breaks down uric acid + mineral stains

💥 Step 3 — Hydrogen Peroxide Paste (the “miracle” stage)
If stains remain:

Mix:
baking soda + hydrogen peroxide → thick paste
Apply generously
Leave 20–30 minutes
Scrub + rinse
👉 This is the closest thing to a “bleaching without damage” solution for plastic