A slight warp in an acacia wood tray is normal wood expansion/contraction and usually doesn't affect its use. Main Cause: The environment is too dry or too humid, causing the wood to shrink or swell unevenly. Quick Fixes: 1. Weigh it down: Place the tray with the warped (bulging) side down and put heavy objects (like books) on top for a day or two. 2. Add moisture (if air is dry): Place a damp towel on the warped side and carefully iron it, then immediately weight it down.