Does anyone know if I can just scrub this mold off my crawlspace door?

You're likely looking at localized mildew or surface mold caused by condensation rather than a massive toxic outbreak, especally since you mentioned the wood is still sturdy. Even in a crawlspace that feels dry, those access doors act as thermal bridges where warm air hits a cold surface. That bottom edge is usally the coldest spot, so any humidity in the air settles right there and creates the perfect environment for splotchy growth to start.

Check the exterior of that wall to see if there's a hose bibb or a gutter downspout nearby. Sometimes water wicks through the framing from the outside even if there aren't any actual plumbing pipes in the immediate area. If it’s just on the door and frame and hasn't jumped to the insulation or the floor joists, you’ve definitely caught it early enugh to handle it yourself without calling in a remediation crew.

Vinegar is actualy your best bet for this instead of heavy-duty bleach or harsh cleaners. Bleach is mostly water and can’t actually penetrate the porous surface of the wood; it just kills what's on top and leaves the roots behind to grow back. White vinegar has acetic acid that gets into the grain. Spray it on, let it sit for at least an hour, and then scrub it down with a stiff brush. Wear an N95 mask while you do it just to be safe so you aren't breathing in the spores you're agitating. Once the wood is completely dry, you’ll want to sand it down and apply a high-quality **exterior-grade sealer** or a mold-inhibiting primer. If you just wipe it and leave it bare, the spores will find those same damp spots the next time the temprature drops. Adding some weatherstripping around the frame can also help keep that temperature differential from causing more condensation in the future.

I had a similar issue with a closet door near my laundry room and was totally freaked out it was the dangerous kind of mold. I ended up using the vinegar trick and it defintely works, but the smell lingers for a bit! One thing I’m wondering though—if I put that weatherstripping on, does it make the door harder to open? My crawlspace latch is already pretty finicky and I don't want to have to kick the door just to get it to seat right. Also, is there a specific brand of that mold-inhibiting primer that's better for beginners? I ussually just buy the cheapest stuff, but maybe that's why I have issues.

For that finicky latch—try using thin EPDM rubber tape rather than the thick foam stuff. It compresses much better and ussually won't mess with the closing pressure. If it’s still acting up, you can usually just file down the strike plate hole or shift it a millimeter or two to give the latch some breathing room. I’d also look at the hinges. If they’re even slightly rusted from the moisture, they’ll pull the door out of alignment, making that bottom corner rub. A quick hit of silicone spray does wonders for keeping the action smooth after you finish the cleaning and get that sealer on.

If you're worried about that vinegar smell lingering, try mixing in a few drops of tea tree oil. It’s a natural antifungal and helps mask the sour scent. Just make sure you really scrub it into the grain with a nylon brush. Also, check if the bottom of the door is acutally touching the concrete floor or dirt. If it sits flush against a damp slab, it'll just keep sucking up moisture like a straw. I had to trim about a quarter-inch off my last crawlspace door to get some air moving under it, and that stopped the mold from coming back way better than any sealer did.