In my Mann filter, there is cotton in the bypass but it is well contained within filter paper/cloth that surrounds the whole bypass section. I never find any of that material in the full flow section, and I didn't find any in the lifter oil galleries or the lifters themselves. I conclude, that the cotton waste doesn't ever enter the engine since it isn't caught in the full flow section or the smallest lowest flow galleries and parts within the oil system.

I am not sure I posted the threads on them but the issue with the Bypass Section of the stock type Filters is that none of the Filter Companies have any idea what level of filtration resutes from it.

Next is the Cotton Waste Filling in the Bypass Section of the Oil Filter varies quite a bite between makers. Some have a lot of Cotton and others have about 1/3 other junk besides Cotton. Some of the Filter have the Cotton Waste packed tight in others it is kind of loose.

If you can locate the threads there is pics of the stuff that is inside of them.
I am not sure what pics I have avaliable but will try to find one just as an general example.

The above was not an issue for me either. What was the issue for me is that none of the Companies that use the Cotton Waste inside of their Filters know what they filter down to. If you don't know that how do you do any quality control on them?

Next was the different Filter Makers use different qualities of Cotton Waste and they some are packed tight and some are not packed tight.

ForcedInduction has a thread where he bought an inexpensive Filter Base on someplace like eBay and used a spin-on Amsoil bypass Oil Filter (the element was around $40 each).

However, you do not have to change the spin-on filter till it is plugged and you can tell by feeling the Oil outlet line. When the Filter is plugged your outlet line will be cold after the Engine has been on a long drive.