Most of the time, this will occur when too much of the product is applied in one coat, or too much pressure is used when polishing it off.
Waxes: Use less than you think you may need and remember that when polishing it after application, you do not need a lot of pressure – You are polishing/buffing it, not burnishing it! Watch the Gloss Finishing Wax and Microcrystalline Wax Two Minute Tutorial videos to find out more.
If you get streaks, you are pressing too hard and you will need a hot air gun to melt the wax into the surface before buffing it again.
Sealers: Cellulose sealers such as ours contain solids that when heated too much, essentially ‘congeal’ into a solid mass which can be pulled around a piece in a streak. This will only occur when you are attempting to burnish it dry and put too much heat into the piece. If left to dry thoroughly without any encouragement, you reduce the risk of this happening.
However, if you burnish your finish that is over the top of the sealer, you risk melting and congealing the sealer. Keep your buffing/burnishing as light as possible to avoid this problem.