Logging means storing data for ex post analysis purposes.
By deleting data from logs for cosmetic reasons, you are going to reduce your future analysis capabilities.
Rather than wilfully ignoring what analysis results are already available, I would recommend to act on it.
Find the device that issues those requests and configure it to cease them.
If that's not possible, get rid of the device.
If you want to keep the device, consider configuring it to use a public DNS server so it won't spam your logs.