Identifying Your Fogging Type
Before choosing a fix, identify which type of fogging you have. Condensation fog is temporary — it appears when temperature or humidity changes and clears on its own as conditions stabilize. It looks like surface moisture beads or a breathed-on glass effect and is usually on the inside surface. If your fog comes and goes with weather changes, condensation is the cause.
Chemical film fogging is permanent until cleaned. This occurs from off-gassing of plastics inside the case, cleaning products that left residue, or airborne contaminants (cooking grease, candle smoke, cigarette smoke) that deposited a film on the interior. Chemical film typically looks like a uniform milky haze that doesn't change with temperature and is slightly tacky or leaves a smear when touched.
Scratch-induced haze is a physical surface change — micro-scratches from cleaning with abrasive materials that scatter light rather than transmitting it. This looks like frosting or fine scratches visible in strong light. Unlike the first two types, it cannot be removed without polishing the surface, and it's caused by how the case has been cleaned in the past.
Fixing Condensation: Controlling Humidity Inside the Case
Condensation forms when warm, moist air enters a case and then cools against the cooler glass or acrylic surface. The fix is humidity control inside the case. Silica gel packets placed inside the case absorb moisture from the air, maintaining lower relative humidity inside than outside and preventing condensation. Use indicating silica gel (blue beads that turn pink when saturated) so you know when to regenerate or replace them.
For cases in humid climates or near moisture sources (kitchens, bathrooms, or coastal environments), use rechargeable desiccant containers — small units with silica gel that can be dried in the oven and reused indefinitely. Place one per case shelf level for best results. Replace or recharge them every 1–3 months depending on your humidity level.
Avoid moving cases between significantly different temperature environments (like from a warm room to a cold garage and back) without allowing adequate equilibration time. Rapid temperature change causes moisture in the warm air to condense on cold surfaces. If you need to transport or relocate cases, allow them to equilibrate to the new temperature before opening them to prevent condensation forming on the figures inside.
Removing Chemical Film from Acrylic and Glass
For glass panels, a solution of equal parts white vinegar and distilled water applied with a lint-free cloth removes most chemical film contamination. Wipe in straight strokes rather than circles to avoid leaving swirl marks. Follow with a clean dry lint-free cloth. For stubborn film, a small amount of rubbing alcohol at 40–50% concentration on a cloth works effectively on glass without risk of surface damage.
Acrylic panels require more care than glass. Many cleaning products safe for glass are not safe for acrylic — alcohol at high concentration, ammonia-based cleaners (Windex and similar), and acetone all permanently cloud or crack acrylic. For acrylic, use only products specifically labeled as safe for plastic and acrylic: Brillianize, Novus 1, or a plain 50/50 distilled water and dish soap solution followed by thorough rinsing.
Apply any cleaning product to the cloth first, never directly to the case panel — this controls the amount used and prevents excess product from reaching seams or hardware. Work in sections, cleaning and drying one panel fully before moving to the next. After cleaning, buff the dry panel with a fresh lint-free cloth to remove any remaining haze from the cleaning product itself.
Polishing Out Scratch Haze from Acrylic
Fine scratches from paper towels, rough cloths, or abrasive cleaners produce a surface haze on acrylic that's distinct from chemical film. This requires polishing, not cleaning. Novus 2 Fine Scratch Remover is the standard product for this: apply a small amount to a clean microfiber cloth and work in circular motions over the scratched area, then buff off with a second clean cloth. For glass, a jeweler's polishing cloth or car headlight restoration compound (applied carefully and in small amounts) works similarly.
Deep scratches that are individually visible require progressively finer sandpaper (starting at 400 grit, progressing to 800, 1200, 2000) followed by polishing compound to restore optical clarity. This is a significant undertaking and is usually only worthwhile for expensive custom cases or large acrylic panels. For standard display cases, replacement panels are often more practical than refinishing heavily scratched ones.
Prevent future scratch haze by establishing the correct cleaning tool: microfiber cloths specifically for optics, photography, or eyeglasses are the safest choice for any display case surface. Paper towels, kitchen cloths, and standard cleaning cloths all have enough surface roughness to leave micro-scratches on acrylic. Making this one tool switch eliminates the main source of progressive scratch haze.