Condition and rubbing is the problem. If you have no rubbing or condition problems then you should be OK. If you're concerned about tracking it in from outsid

Condition and rubbing is the problem. If you have no rubbing or condition problems then you should be OK. If you're concerned about tracking it in from outside, or improper renovation, you can apply the tests to dust too, which is where any pulverized lead in the air would come from.