Lately, I don't always have time to clean up the car on a weekly or bi-weekly basis. When I wash it, most bugs come off the clear bra relatively easily, but there are some left over bits of bugs that just stick tenaciously. My current method is to just keep gently scrubbing it and soaking over the hour or so it takes to wash the car. This works for some but not all. I've been using Optimum car wax after every washing since the day I bought the car. Any suggestions for getting those tough bug bits of a clear bra?