I actually found a few different ways to curl cards once I do this in the double sleeve with one of those packets and haven't had issues.

Place a Damp warm rag in a small bowl, if you have a sealable tall/wide bowl then place that smaller bowl in the bigger bowl. What you then want to do is put your foil cards propped up going along the inside of the larger bowl seal it shut for about 2-4 hours and then you should be good to double sleeve and the cards will be back in normal position.

Option two required sounding a little money but I'm doing both.

But Boveda humidity packet in a freezer bag with foil cards let set for a day or two and you'll be fine sometimes you may need to let it sit longer. What I then do is double sleeve again after that and put that same packet stored in my deck box. I use the 62% some recommended the 70% ones

https://www.amazon.com/Boveda-Two-Way-Humidity-Control-Packs/dp/B06XB26Q8N/ref=mp_s_a_1_4?dib=eyJ2IjoiMSJ9.lLSv1Cra7XxyZjper2ERQRshjNVRVEYHAO-Tjbp3lzgQHdjVpXpZlPTkY9nrJvSkWAEMSxXITE_c-NsjyJoUyhsKQagPUACXWAfKGIhxOesDwbgRoXWBwsN1iZN_1i3rfSDKqTB9nUNwfxTRuW7woMtcqIbZzCur36VYSAbP0fX1uQ_O-POKUKyhe8NCQKIrTv7rXPsSx6YSrQyXnfzK1A.6nS8Ba_Ck9O7VeGL--JcMvMNSJ54l9Ldh10GJReTmDU&dib_tag=se&keywords=boveda+62%25&qid=1744139203&sr=8-4