Why disassemble?
If you are going to disassemble your mouse to clean it, think again.
Yes, if you are careful and dextrous you can successfully disassemble and re-assemble it - with a risk of breaking the ring, unsightly over-glueing, etc.
And how long will it be before you have to do it all over again (hoping you didn't use too much glue the last time...)? 3 months?
I had the scroll problem and thought I'd have to disassemble, as my vigorous cleaning didn't work. I tried again, and now it's fine.
The process I used (found on the web) was to place a sheet of photocopy paper on a flat surface and rub the (up-side down) mouse scroll wheel over it in every direction - back & forth, side to side, clockwise circles, anti-clockwise - tilting the mouse at different angles. I was very vigorous.
You can see if it's working - the paper collects little dots of grunge. Keep going until the scroll wheel works or grunge stops coming out.
If it doesn't work the first time, keep trying. I did, and it saved me some fiddly work, some time, and the risk of wrecking the mouse.