The Green Train Bridge in San Jose has become several taggers favorite target.

Caltrans and the city say they've tried just about everything to keep graffiti off the bridge over Highway 280, near Bird Avenue. Historically, taggers have repeatedly defaced the bridge with their monikers.

Three years ago, NBC Bay Area discovered that someone even put grease around the bridge so taggers couldn't scale it. Nobody took credit for the tactic, but the bridge remained tag-free for two years before taggers eventually found a way.

Caltrans, Caltrain, Samtrans and the City of San Jose have now cleaned it up again. This time a recent visit did not find any grease, but some are asking if the tactic should be used again.

It's still not clear who put the grease up there three years ago or whether they'll try the tactic again. What is clear is that you can expect the chess match to continue.

NBC Bay Area has reached out to Caltrans to see if they did anything after the cleanup to try and deter graffiti.