In a memo issued Friday, the House ethics committee attempted to clear up lingering confusion over the ban on privately funded travel adopted earlier this year.

The guidance notes there is still some room in the rules for private groups or companies to fund travel for lawmakers and staff. Groups that don’t employ lobbyists still can fund trips, as long as they are pre-certified by the committee and are followed up by filed disclosures.

Certain trips sponsored by groups with lobbyists are still OK: Universities are exempted from the ban, and any group that employs lobbyists can pay for Members and staff to go on overnight trips, with a second night’s stay cleared under special circumstances. But for the overnight trips, lobbyists themselves are banned from attending and can have only negligible involvement in helping set them up.

Before Members and staff jet off on any trip, they must certify that lobbyists have had nothing to do with it. And they have to prove the travel is relevant to their official duties. Sponsors have to provide their own certification to invitees that the trip is within the rules. Each Member and staffer has to submit both forms to the ethics committee for approval.

Business class is still an acceptable form of travel. A first-class, private or chartered flight, however, is allowed only if disability or security concerns make it necessary, the flight is longer than 14 hours or its cost doesn’t exceed the business-class rate.

If the trip is to an event not organized around the lawmaker or staffer’s participation, such as a trade group’s annual conference, the traveler can stay and eat with everyone else.

For events tailored for Congressional participation, however, the committee is allowing “reasonable” lodging and food expenses, based on federal per diem rates. The location of such a trip must be necessary to its purpose, the memo states. That is, a fact-finding trip on an industry should visit a factory, not a resort.

After they get back, Members and staff have 15 days to file disclosures of their expenses, and the meetings and events they attended, according to the memo.