The 737 Classic FCTM discusses use of reverse after landing.
Quote: The thrust levers should be positioned to reverse idle by taxi speed then to full down after the engines have decelerated to idle. Unquote.
This suggests that ingestion is not a problem at reverse idle.
Depending on your point of view, it could be argued that providing you don't go above reverse idle (approx. 22% N1) you could slip into reverse idle without harming the engines in order to keep taxi speeds from building up in a long taxi and thus minimising brake heat increase.