Card Storage and Handling: Penny Sleeves, Semi-Rigids, Toploaders, Humidity & Light

No grader publishes a full storage standard for trading cards. PSA and CGC publish how they want cards sleeved and held when a submission arrives; temperature, humidity, light and safe plastics come from the conservation guidance the Library of Congress, the National Archives (NARA) and the Northeast Document Conservation Center (NEDCC) write for paper and photographs. This page combines the two. All sources were read on October 14, 2026; no brands or products are recommended.

Holders at a glance

Common card holders and what the graders say about them
Holder	What it is	Grader rules	Notes
Penny sleeve	A thin, clear, open-ended plastic sleeve for a single card.	PSA wants a clear penny sleeve on every submitted card and warns that solid or opaque sleeves can cause delays. CGC asks for a protective sleeve on every card.	The first layer, under any rigid holder.
Semi-rigid holder	A stiffer sleeve that a sleeved card slides into.	PSA requires one for submissions, 3 5/16 × 4 7/8 in for standard cards, with both sides of the card visible. CGC asks for one sturdy enough for it to remove the card safely.	The usual holder for sending raw cards.
Toploader	“A rigid plastic case with one open end” (Wikipedia).	PSA's shipping guide says not to use toploaders, tape, pull tabs or sticky notes. CGC's shipping page does not mention them.	PSA gives no reason; the rule covers submissions, not home storage.
Graded holder (slab)	A sealed holder with the grader's label.	PSA describes a tamper-evident holder with a strong weld; CGC an ultrasonically welded case that resists impacts and tampering.	Neither page claims UV protection for the holder itself.
Storage box	A box for sleeved cards or slabs.	—	NARA recommends board that is lignin-free and acid-free or buffered, kept on a shelf.

Fit matters for thick cards. PSA's FAQ says it uses a separate thick-card holder for 25- to 40-point cardstock, that copies of the same card and parallel can differ in thickness, and that it picks holder sizes itself.

The card: handled with clean, lotion-free hands (NARA).
Penny sleeve: a thin, clear, open-ended sleeve; PSA asks for clear sleeves, not solid or opaque ones.
Semi-rigid holder: PSA specifies 3 5/16 × 4 7/8 in for standard cards; CGC asks for one sturdy enough to remove the card safely.
Toploader: a rigid case with one open end; PSA's shipping guide says not to use toploaders in submissions.
Box on a shelf: lignin-free, acid-free or buffered board, away from pipes and windows (NARA).
Light: no direct sunlight; light damage is cumulative and irreversible (Library of Congress, NEDCC).
Temperature: room temperature or below (Library of Congress); NARA says below 75°F.
Relative humidity: NEDCC's storage range is 30–60%; NARA says below 65% to prevent mold and reduce insects, and not below 15%, which can cause brittleness.

Generic, unbranded card and holders drawn by Crazy Uncle's Card Notes from PSA's Shipping Guide, CGC Cards' shipping page and the Library of Congress, National Archives and NEDCC storage guidance cited below. Not to scale; no real card, label, product or grader branding shown.

Which plastics are safe

Conservation guidance names a short list of plastics for storing paper and photographs, and one to avoid. If a sleeve's or holder's material isn't stated, NARA's advice on unknown plastics applies.

Plastics for storage, as conservation sources describe them
Plastic	Verdict	What the sources say
Polyester	Recommended	NEDCC calls it the most inert, dimensionally stable and rigid of the three; the Library of Congress recommends polyester sleeves. It can build static that attracts dust (NEDCC).
Polypropylene	Acceptable if uncoated	On the Missouri State Archives' list of the only plastics to use. NEDCC notes that surface coatings on some polypropylene are proprietary and can't be evaluated.
Polyethylene	Acceptable if uncoated	Also on Missouri's list. NEDCC says low-density polyethylene contains anti-block and anti-slip agents that could damage photographs.
PVC (vinyl)	Avoid	NEDCC says PVC is not chemically stable and is unacceptable for photographic storage; NARA and the Missouri State Archives also say to avoid it.
Unknown plastic	Avoid	NARA lists unknown plastics alongside PVC among materials to avoid.

Temperature, humidity and light

Environment guidance for paper collections
Factor	What the guidance says
Temperature	Room temperature or below (Library of Congress); below 75°F (NARA); 55–65°F for regularly used storage (NEDCC).
Relative humidity	About 35–50% (Library of Congress preservation FAQ). 30–60% (NEDCC). Below 65% to prevent mold and reduce insect activity, and not below 15%, which can cause brittleness (NARA).
Stability	A stable environment (Library of Congress). Rapid humidity swings make paper move, which can distort it (NEDCC).
Light	Minimal exposure, none direct or intense (Library of Congress). Damage is cumulative and irreversible: fading, yellowing, embrittlement (NEDCC, National Gallery of Art). UV does the most harm, but visible light also damages (NEDCC).
Display	NEDCC: most collection materials can be exhibited three to four months at 50–150 lux, less at brighter levels, never in direct sunlight.
Location	Not in damp basements, garages or hot attics; away from pipes, windows and roof leaks; on a shelf (NARA). Exterior walls track the outdoor temperature (NEDCC).
Pests	Away from food and water, which attract insects and rodents (NARA).

Slabs are not exempt. PSA's and CGC's holder descriptions cover welds, tamper evidence and clear optics; the UV features they mention are anti-counterfeiting inks on the label, not protection for the card.

Handling a raw card, step by step

Prepare the space. NARA's handling tips: have a clean, clear surface ready before taking items out, and don't eat, drink or smoke nearby.
Wash your hands, skip the lotion. NARA says lotion can stain paper and that clean, lotion-free hands will not.
Decide on gloves. NARA advises against cotton or plastic gloves for paper because they catch and tear it, transfer dirt and make handling awkward; it uses nitrile gloves for photographs, which fingerprints can permanently stain. Neither rule is written for cards specifically.
Sleeve first. Slide the card into a clear penny sleeve, then the sleeved card into a semi-rigid holder or toploader.
Before a PSA submission, move cards out of toploaders into 3 5/16 × 4 7/8 in semi-rigids, both sides visible. The full packing routine is in how to submit cards for grading.
Box and shelve. Store sleeved cards in a lignin-free, acid-free or buffered box on a shelf, away from pipes, windows and exterior walls.

Damage that handling causes — corner dings, edge chipping, surface scratches, creases — is defined in the card condition glossary.

Storing graded cards

Tamper evidence is the point. PSA's FAQ says that if someone tries to violate its holder, it will leave some evidence; that is also why opened and reglued holders are a red flag (see how to spot a fake slab).
Stacking. CGC says its holders lock and stack together for storage and display.
Scratched or worn holders. CGC's ReHolder service moves a card into a new holder without changing its grade, provided the card is still in its original CGC holder. PSA lists reholdering among the services available through a Classic Submission.

Quick checklist

Clean, clear surface; clean, lotion-free hands
Clear penny sleeve, then a semi-rigid or toploader (semi-rigid only for PSA submissions)
Polyester, polypropylene or polyethylene — never PVC or unknown plastic
Lignin-free, acid-free or buffered box, on a shelf
Room temperature or below; under 75°F (NARA)
Relative humidity 30–60% (NEDCC); never above 65% or below 15% (NARA)
No direct sunlight, limited display time — slabs included
No basements, garages, attics or exterior walls

Card storage and handling