I just did this yesterday, so I'll tell you how I do it.
1. If the seals are nasty, use APC and MF towels to clean them. A paint brush may help as well. Mine aren't nasty, so I just used some IUDJ and a black MF towel. Use a black towel if possible - as your towel likely will have stains.
2. Use 1Z Gummi Pflege. However the dispenser can be tricky. It works well when the bottle is upside down, just OK when the bottle is on it's side, and not to great when the bottle is upside down. You need to squeeze the bottle, sometimes with some force to dispense the product. So, I apply it heavy on the top seal area, and then spread it on the seals with a folded blue paper shop towel. The towel quickly becomes soaked in product, so it's works pretty well. If you don't evenly spread the product with a towel, it can get drippy and dry splotchy. The foam on the bottle doesn't spread it perfectly IMHO.
3. The whole top of the 1Z stuff pops off. Not the foam piece, but the stem it's attached to. After using it, pop it off an clean the foam with pad cleaner in the sink. Since I'm nuts about cleaning this type of stuff, the foam may come unglued. I'd rather have unglued foam than dirty foam. If it comes unglued, just clean it and dry it. Then, you can Krazy Glue the foam back. It doesn't come unglued after that.
4. The 1Z lasts quite a while. 6 mos. to a year.