And be very careful to not overuse the cartridge. With even the best cleaning cartridge, think about what it is doing. The cleaning strip passes through and picks up contaminants. If it doesn't, it's not doing the job at all and is useless. If it is doing its job, the strip will become more and more contaminated - and then it's going to begin to deposit while it cleans, or at best just move the contaminants from place to place.
Most professionals prefer to do the job manually.
It takes only a few extra minutes and guarantees that the job will done correctly and thoroughly. It's also much less expensive. Do NOT use standard rubbing alcohol off the shelf. Go to the counter and ask the druggist for technical grade. Keep it tightly capped.