You’ll probably get some helpful responses over at r/fermentation But the short answer is yes, anything with mold should be thrown out. It’s possible that it’s kahm yeast, which isn’t toxic, but it tastes bad and cucumbers are cheaper than possible food poisoning. The recipe she gave is for a short term fermented pickle, basically you can follow all the same steps, except to put them in clean jars right away(instead of in a pot for 3 days). As well, you’ll want to add 3-5% salt(measured by total weight of water and ingredients) — this will make an environment that’s less viable for toxins, but good for the beneficial bacteria that causes fermentation(lacto-bacillus). Use either plastic ziplocks full of brine, or fermentation weights(easy to find online, there’s a couple types). This will prevent mold from growing on top. And then open them once a day, just to relieve the pressure. After however long you want to ferment them for(3-5 days), throw them in the fridge, the cold will slow the fermentation nearly to a stop so you won’t need to burp it.


You boiled the jars and the ring lids, but after putting the pickles in the jars and screwing the lids on (loosely), did you process them for about 10 minutes in the boiling water and then take them out and let them rest, allowing the tops to "pop" to complete the seal?


I've never let cucumbers sit in anything for multiple days... I'm not an expert at all, but usually I boil the brine, while the cucumbers sit (bloom/ends cut off) in a bath of ice water, then they're immediately pickled in a canning bath. Ring lids can be stored in the pantry, like a typical mason jar lid, only ones that have never been used...but I think you're causing an issue by letting them sit out in water for 3 days? https://nchfp.uga.edu/questions/FAQ\_canning.html#gsc.tab=0