Do it for the 14 yr olds stuff, he is old enough to know better, the 10yr old is just copying him, maybe just hide his.
Basically I just wouldn't go in their pits anymore. Don't do anything for them if its in their room.
My mum had to do this for my older brothers when they were 14 and 13 and sharing a room with their little brother because of exactly this, the whole room would be full of their crap by the end of the week and she actually have to clear a path to get to her younger sons bed to put him to sleep (Little brothers bed was on one side of the room, they were on the other side in bunk beds)
When they were at school one day she actually went in their room , took the carpet up and painted a line on the floorboards (even giving the older boys more room on their side) and replaced carpet with rugs. All their crap was piled on their beds. Basically the ground rules were set as follows: Any of their crap ends up on little brothers side of the room? Goes in the bin. They want clean clothes? Bring it downstairs to go in the washing basket. They taken plates and cups upstairs in their room and not bought them out? No pocket money. They take food up and it starts to rot? No pocket money and they have to clean out the rabbits cages. She would also make them hand over their school uniforms during the week (weds and Fri) so she could wash them all over the weekend for school week as she knew they wouldn't bother to bring them downstairs.
The reason my mum did this? It was HER house, NOT their house. As soon as they moved out they could be as messy as they wanted to be.
But this was HER house, dad and her had worked their arses off to get it and she wasn't going to let them ruin just because they couldn't be arsed to pick things up from the floor.
It worked, in fact both my older brothers are very tidy adults and realised my mum was right when they got their own places as adults.
Also both my brothers loved my mum and were with her holding her hands when she died and to this day we can't bring up her memory with without my older brother having a little weep because he still misses her so.
It didn't "scar" them for life, just taught them a valuable life lesson that you can't just do what you want in life, that girls/boys (depending on sexual preference) will not find you attractive if your room is a tip and you smell rank and respect someone else's property and your belongings.
But then again we were pretty poor so they didn't have a zillion toys and books to clutter up the place!