Next you have to realize that Soviet soldiers were largely uneducated people, who lived simple, peasant lives when not soldiering all over the place. So, when they were on the shitter and grabbed whatever discarded sheets were nearby, they probably had no way of knowing they were wiping with classified documents. Whatever secrets these papers revealed likely meant nothing to them, except they helped provide a fresher feeling between the legs.
When US and UK forces got wind of this, they launched Operation Tamarisk, because "Operation Dig Through Garbage For Paper Wads Covered in Human Shit" did nothing to attract volunteers. Spies, who probably enlisted with visions of Sean Connery in a tuxedo dancing in their heads, would literally collect all the discarded crap-filled documents they could find and bring them back to friendly territory to be cleaned, decoded, and analyzed.
AP via Armahellas.com
"Please do not wipe your ass on this. -Stalin"
If that already sounds like the worst job in espionage history, it gets worse. Because they found that the Russians didn't just toss shit-coated secret in the trash; they also threw away goddamned body parts. Any limbs that were amputated or blown off, due to faulty grenades or other such weaponry, were literally chucked in the garbage, like a dinner plate full of chicken bones. Once word of this got out, U.S. and U.K. spies went about bringing those back, as well, so their superiors could deduce what kind of shrapnel the Soviets were using in their grenades. That, and to entertain the kiddies on base with the world's most gruesome and disturbing puppet show.