Aside from checking and double checking your pockets for tissues, papers, etc. this question kind of stumped me. However, I did a little research and found a couple of interesting bits of info for you on how to clean the inside of washing machine.
1. Adding 1/2 cup of white vinegar to the wash load will prevent lint from clinging to your clothes. (source). I haven’t ever done this but if you are having a lint issue, and the next tip doesn’t help, I think it’s worth trying.
2. Clean your filter. Personally I didn’t even know that my washing machine had a filter! I mean it makes sense but my washer is a hand-me-down so I don’t have a manual or anything to tell me about cleaning my filter. (If you don’t have a manual for your machine look online and I’m sure you will be able to find one to tell you how to clean your particular model). I was very curious about this so I had to try it out.
Good luck and happy washing!