Hiya! Your girls are so cute! Welcome to the forum 
For the cage, I can't tell if you made the cardboard bedding yourself but it's very hard to do so properly. The best beddings are aspen, kiln-dried pine, hemp, and equine-grade cardboard! The cardboard is usually hard to find in the US but I'm not sure about the Netherlands. Avoid paper bedding at all costs! Misinformation online about rats is rampant, especially with rat care changing because of increased research. Paper bedding is in no way safe for rats! Fleece is also not a good option unless it's for a hospital cage where bedding would stick to a rat's wound.
Hemp is the most hypoallergenic but it may be hard to find, I'm not super familiar with the Netherlands but I believe it's easier to find in some parts of Europe. Aspen and pine (kiln-dried) are absolutely wonderful though!
For cage cleaning, you'll need to change the bedding, wash hammocks (or put in clean hammocks), wipe down the bars of the cage, and wipe down other surfaces (surfaces of hides, bins, floors, etc.)! The wood will need to either be boiled once a week (it's notoriously hard to clean wood, especially with all the ammonia rats produce) or thrown out and replaced. The best cleaner to use is just soap and water! I use dawn dish soap like many other owners, but any kind of unscented dish soap is fine! You can go over the surfaces again with diluted vinegar (half vinegar, half water) if you're worried about the smell, as vinegar is an odor remover! It isn't suitable for cleaning everything though, since it doesn't really disinfect.
You'll need to have lots of hammocks, bins, baskets, and other hides to fill up the empty space in the cage! Any drop or open space more than the length of your hand (downward) can result in injury if the rat falls. I can send some good cage inspirations if you'd like! You can also diy hammocks and get cheap baskets from a dollar store! They don't need anything fancy.
You'll see wheels in some cages, and if you'd like to have one, make sure you get or make one that has a diameter of 14 inches for females or 16 inches for males. I can provide a website that sells suitable wheels if you're interested!
For food, I believe Science Selective Complete Rat and Mouse is the best in Europe! You'll feed 15-20g per rat per day. Pellets are the best kind of food since mixes are very difficult to get right and can be dangerous if they aren't made perfectly- and even a recipe that someone else has made will never be perfect. Treats like plain cheerios, dry pasta, baby puff snacks, and baby food are very good!
Here are some sources! The Google document is just a short version of care I wrote, with sources, and the other one is from a very reputable breeder!
rat explanation - Google Docs
Rats 101 | Silver's Rattery (silversrattery.co.uk)
For the cage, I can't tell if you made the cardboard bedding yourself but it's very hard to do so properly. The best beddings are aspen, kiln-dried pine, hemp, and equine-grade cardboard! The cardboard is usually hard to find in the US but I'm not sure about the Netherlands. Avoid paper bedding at all costs! Misinformation online about rats is rampant, especially with rat care changing because of increased research. Paper bedding is in no way safe for rats! Fleece is also not a good option unless it's for a hospital cage where bedding would stick to a rat's wound.
Hemp is the most hypoallergenic but it may be hard to find, I'm not super familiar with the Netherlands but I believe it's easier to find in some parts of Europe. Aspen and pine (kiln-dried) are absolutely wonderful though!
For cage cleaning, you'll need to change the bedding, wash hammocks (or put in clean hammocks), wipe down the bars of the cage, and wipe down other surfaces (surfaces of hides, bins, floors, etc.)! The wood will need to either be boiled once a week (it's notoriously hard to clean wood, especially with all the ammonia rats produce) or thrown out and replaced. The best cleaner to use is just soap and water! I use dawn dish soap like many other owners, but any kind of unscented dish soap is fine! You can go over the surfaces again with diluted vinegar (half vinegar, half water) if you're worried about the smell, as vinegar is an odor remover! It isn't suitable for cleaning everything though, since it doesn't really disinfect.
You'll need to have lots of hammocks, bins, baskets, and other hides to fill up the empty space in the cage! Any drop or open space more than the length of your hand (downward) can result in injury if the rat falls. I can send some good cage inspirations if you'd like! You can also diy hammocks and get cheap baskets from a dollar store! They don't need anything fancy.
You'll see wheels in some cages, and if you'd like to have one, make sure you get or make one that has a diameter of 14 inches for females or 16 inches for males. I can provide a website that sells suitable wheels if you're interested!
For food, I believe Science Selective Complete Rat and Mouse is the best in Europe! You'll feed 15-20g per rat per day. Pellets are the best kind of food since mixes are very difficult to get right and can be dangerous if they aren't made perfectly- and even a recipe that someone else has made will never be perfect. Treats like plain cheerios, dry pasta, baby puff snacks, and baby food are very good!
Here are some sources! The Google document is just a short version of care I wrote, with sources, and the other one is from a very reputable breeder!
rat explanation - Google Docs
Rats 101 | Silver's Rattery (silversrattery.co.uk)
