What to do when we can't reproduce a bug?

Finding a bug can happen at any point of time. It can happen during exploratory testing or while running automation suites or doing manual testing.
Once we find a bug we are as happy as can be :). But what if developer/you can't reproduce it :)

Even after explaining the steps clearly, sometimes we cannot reproduce the bug with the same steps which is really frustrating.

There will be various reasons for not reproducing a bug easily. It can happen
1. In specific scenario
2. On specific environments
3. Under Specific conditions. etc..

In such condition what we can do to reproduce the issue?

Option 1:

1. Open the browser in incognito/private mode
2. Clear the cache
3. Open the developer tools and navigate to console.
4. Start reproducing it again by trying different combinations.

If you are able to reproduce it HURAAYYYYYYY!!! pass all the information that you got it from console.

Option 2: 

We cannot trace an issue if we do not have enough information.
1. Send out a mail asking if any developer/tester faced this issue and ask to add the logging if necessary?

Option 3:

1. Record your screen and start reproducing it. I know it takes lot of space and memory, but there are tool which can save only last one hour recording which helps.

Option 4:

1. If you have a automated scenario which covers this, keep it in loop and run it.

Option 5:

Remove any extra add-ons that you have enabled in your browser.

For Applications, that are installed on Desktop, most likely Options 2 & 3 would suffice.
You can pick any option which feels easy and apt for you.
If you were able to reproduce the issue successfully, we achieved it.

If we cannot reproduce in any ways, then decide within the team what is the impact in moving to future release and take the necessary actions accordingly.