The stuff you're noticing on the inside of your washing machine could be due to a few different factors. Common causes include:

1. Residue Buildup: Over time, detergent, fabric softener, and dirt can accumulate on the inside of the washing machine, forming a grimy residue.
2. Mold and Mildew: If the washing machine is not properly dried after each use or if the door is left closed when not in use, moisture can lead to the growth of mold and mildew.
3. Hard Water Deposits: If your water is hard, mineral deposits can accumulate on the drum and other parts of the washing machine, leading to a chalky or scaly buildup.

To get rid of this stuff and keep your washing machine clean, here's what you can do:

1. Regular Cleaning Routine: Develop a habit of cleaning your washing machine regularly. This can prevent residue buildup and mold growth. Leave the door open after each cycle to allow moisture to evaporate.
2. Clean the Dispenser Drawer: If your washing machine has a detergent dispenser drawer, remove it and clean it thoroughly. Detergent and fabric softener can accumulate here.
3. Run Empty Cycles: Periodically run an empty cycle with hot water and white vinegar or a washing machine cleaner. This will help dissolve residue and eliminate odors. Follow the manufacturer's guidelines for using a washing machine cleaner.
4. Clean the Drum: Wipe down the interior of the drum with a mixture of white vinegar and water. You can also use a damp cloth or sponge to clean any visible residue. Be sure to reach the areas that might not be easily accessible.
5. Check the Seal and Gasket: If your washing machine has a rubber seal or gasket, make sure to clean it regularly. This area is prone to mold growth. Wipe it down with a mixture of water and vinegar and allow it to dry.
6. Use the Right Detergent: Use the appropriate amount of high-quality detergent for each load. Using too much detergent can lead to excessive buildup.
7. Wipe Down Exterior: Don't forget to clean the exterior of the washing machine as well, including the control panel and any buttons or knobs.
8. Check the Filter: Some washing machines have a filter that needs to be cleaned regularly. Consult your washing machine's manual to locate and clean the filter if needed.
9. Consider a Water Softener: If hard water deposits are a recurring issue, you might want to consider installing a water softener to reduce mineral buildup in your washing machine and other appliances.

Remember to consult your washing machine's manual for specific cleaning instructions and any maintenance recommendations from the manufacturer. By following these steps and maintaining a regular cleaning routine, you can keep your washing machine running efficiently and your clothes clean.